I use an "XFX Gforce 6600GT" which has Dual (2) DVI Ouputs and also comes with 2 DVI to VGA Adapters.....The Nvidia Drivers also give you many options on how you want the display to be on both monitors.....
The Card is also very fast (500mhz GPU/1000mhz GDDR3 Memory) so you can Play all of the Newer Games like "Doom 3" , "Half Life 2" and "FarCry" ect....
The card is probably only about $100 US now as I paid $140 Canadian about 6 months ago...the card also comes in AGP or PCI-E Flavors....
Cheers