Eyefinity set up for sure.
[Edit] To answer your initial queries, it depends on the game. Some games, such as BFBC2, TF2, JC2, Crysis, BF3, F1-2010/2011... enable you to see 'more' of the game world, just like extra widescreen. And others such as Mirrors Edge (Hack), Assassins Creed 2.... simply enlarge the image, not so that it appears stretched but I guess it is effectively stretched across all three screens such that you loose some at the top and bottom. So unfortunately there is no direct answer it simply depends on the game. The AMD website has a list of validated eyefinity games, although don't be bounded by this list, there are many more that work perfectly fine, the best resource is probably widescreengamingforum.com.