I think its possible to do MMO like WoW but you need:
A very very good internet connection to hold that much of people and a good comp too.
Alot of DLL like MultiSync but if you want lot of people you a need DLLs that are 10 more powerful that MultiSync (and I'm not saying that MultiSync is not good.)
and finnally, you need to be very good in programming to do a MMO.
But the best thing to do its a ORPG like Guild Wars. Its less hard and its always fun to play.
Hope it helped.
Windows XP,pentium IIII, 1,9 MGZ, 256 mb memory, 128 mb video card ATI Radeon 9200 se s80 'sett squadron back on the assault'