Click on the artists' names to visit their website.
click fo larger view
All of these prints are sold out but you can still purchase them, with varying degree of difficulty/expense from eBay or the Expresso Beans community forum.
Most of these prints have been released by Mondo, the pioneer in this terrain, but other galleries worth following include Gallery1988 (who recently signed a deal with the Academy to release a series of Oscar nominated flims' official prints), Dark City Gallery, Bottleneck Gallery, Dark Hall Mansion and more.
I am by no means an expert so feel free to suggest other links to galleries and artists in the comments.
I've tried to restrict this post to the major artists in the "poster scene" (I know). It is perhaps more interesting to go around unearthing artists who are not as hyped and as a result have much less exposure, despite their obvious talent.