OK, I'm now officially wanting to execute conservatives who keep rewriting the historical record with regard the the Nazi party, usually in hopes of proclaiming them far-left. This is both wrong and a lie. Normally, I'd allow the option of being misinformed but our history has been so heavily influenced by the Nazis (via WW2) and the history is so freely available that someone would have to go out of their way to avoid know the basic facts. Ergo, anyone who tells you this is lying, either explicitely or by omission.
First off, let's deal with the political ideaology of the Nazi party, since this might explain how an extreme-right party came to have the word "Socialist" in it's name (which is the one and only reason to even entertain the idea that the party was on the left). Essentially, the party was founded as the German Worker's Party in 1918 as a unification of the various German nationalist groups that grew up in the chaotic end of World War I. The original leader, Anton Drexler, formed a party platform which included social support to middle-class Germans of Aryan origin (which was the ONLY socialist part of the agenda), nationalism (which included, at that time, anti-semitic views), fierce opposition to both lasseiz-faire capitalism and communism and the glorification of the common "volk" (German for "folk" but carrying connotations of noble farmers and rural manual labour. The way Michelle Bachman uses "real Americans" has similar connotations). While explicitly opposed to communism, the DAP (German Worker's Party) also considered international capitalism as a tool of "international Jewry". From the very beginning, the DAP was opposed to any political ideaology which was non-nationalist and especially those on the left and fought bitterly with the DSP (Social Democrat Party) and KPD (German Communist Party).
Initially, the DAP was tiny. Perhaps to attract new members, the group changed it's name to the "National Socialist German Worker's Party" in 1920. Adolf Hitler was the 55th member. Through a combination of fiery oratory and ruthlessness, Hitler quickly became the dominant figure in the party and became chairman in 1921 whereupon virtually the entire socialist aspect of the party's ideaology was dropped. Thereafter, the party would be governed by the furherprinzip ("leader principle"). In short, what Hitler said was what happened. And Hitler was uninterested in the social welfare aspect of the platform (although it was left in the party manifesto to attract working-class members). Hitler's interests were German nationalism and Antisemitism. When the National Fascist Party rose to power in Italy under Mussolini, Hitler promptly stole a lot of their schtick, such as the brown shirts (the Italian's wore black) and the straight-arm Roman salute. The party continued to grow until they launched the disastrous "Beer Hall Putsch" (an attempted coup) in 1923, after which Hitler was imprisoned and the party was banned.
Hitler was released around Christmas of 1924 and the following year, he refounded the NSDAP. This time around, the party made a great pretence of disavowing force (although, like the British BNP, this was a transparent charade) and admitting women. It was around this time that the SA (stormtroopers") and SS (originally Hitler's personal bodyguard) were formed. Eventually, due to a coup in 1932 and the splintering of the opposition, the NSDAP essentially held power in the Rechstag (although not a majority, the intricacies of Reichstag politics meant that if the Nazis acted in conjunction with other nationalist parties, they could excercise power). In 1933, Hitler was appointed Chancellor by President Hindenburg and the rest is history.
Hopefully, that's somewhat clear now. Fascism is slightly difficult to define but some of the traits which are always included are that it always starts as a working-class, populist phonomena preaching a return to a glorious (and often mythical) past. It usually makes heavy use of whatever the dominant religion is and it is always violently nationalist. Naziism is right-fringe, is that clear?
Right, now for the religious element. This one has two main offenders: Christians who claim that the Nazis were athiests and athiests who claim they were Christians. The truth, as always, is rather more complex. There were four main strands of religious thought within the NSDAP. The first thought of themselves as "good Christians". To do this, they reimagined Jesus as an Aryan, threw out the entire Old Testament as a "Jewish book" and had some very creative interpretations of the New testament but nevertheless, they thought of themselves as good Christians. That faction was probably the majority of the parties rank-and-file, it's functionaries and pavement-pounders, it was certainly the majority of the German army under Nazi control. The second faction, which was probably the majority of the party elite, felt no real religious faith themselves but were more than happy to manipulate the faith of the masses to their advantage. It was probably this faction which was responsible for things like trying to "Nazify" Christmas by putting swastikas atop the tree and on ornaments (yes, that really happened; no, it didn't have much success outside the party). A third faction wished to destroy Christianity and replace it with a kind of pot-pouri paganism, stealing elements of Germanic and Nordic mythologies and relics and collecting and performing rituals with no real understanding of the underlying belief structure of those rituals. Finally, there was a faction of athiests who thought religion was a refuge for the weak. This lot were somewhat influenced by the philosophies of Nietzsche although those philosophies were twisted to adhere to Nazi ideaology (sadly, Nazi propoganda on this front has led to the majority of the public misunderstanding what Neitzsche was actually saying).
Now, Hitler himself made a great many remarks. Some (especially those in "Main Kampf" which was intended for public consumption) were supportive of the Nazi interpretation of Christianity. Others seemed to support paganism, attack Christianity or attack religion in general. Hitler never consistently supported any of the religious factions, instead manipulating and supporting whichever one fitted his purposes best at the time. The upshot is that we now have little idea what, if anything, Hitler actually believed. For every quotation one can find showing a disdain for Christianity, one can also be found supporting it. In the end, we have no idea.
So neither the Christians nor athiests are right to blame the other for Naziism. Both also fail to consider that, as in any fascist structure, understanding of Christianity or athiesm was always filtered through the lens of party ideaology.
EDIT: To reply to Foxwood's dimwitted comment. Obama is neither a Communist or a socialist. The only way to call him either is to completely ignore the actual meanings of the bloody words. Obama isn't even especially liberal, let alone a communist. And it isn't "in" to be a communist or even a socialist (Michael Moore no more represents the left than Ann Coulter represents the right). Fox News and Rush are lying to you. Obama is a very slightly left-of-centre moderate.