Nope, no new drivers should be needed, I'm pretty sure it's windows itself that handles it if your card is capable.
One screen is considered the left screen and the other the right screen. You can move your mouse between the left screen and the right screen via the border in which the two 'touch', so the right side on the left screen and vice versa. You can maximize a window in each screen independently, so you can have like, Microsoft Word on one and Internet Explorer on the other. Just drag the window over and maximize.
Multiple monitors is drived by the software of your graphic card.
You have normaly those choice:
1) Same image on both (clone).
2) Extended Desktop (may have different settings).
3) Horizontal Stretch (both same settings).
4) Single Display (One Display - 2nd off).
With a 8800 nvidia card, download the latest drivers, which you would do anyway.
Right click on either display and select the nvidia control panel. Select the option to configure multiple displays. I think you will want "dual view".
With dual view, both monitors look like one large monitor. You can drag a window from one to the other, and do anything you could on just one monitor. When playing a game, the only main monitor will be used. There may be some games that can use multiple monitors.
I will leave my e-mail up along with some performance monitor on one display while playing a game. If I need to break out of the game, I press the windows pearl button, the game is suspended, and I can do anything I want before resuming the game.
There are also a few multimonitor utilities available that add a bit of extra functionality.. At work I use UltraMon to handle my 3 monitors (1 lcd rotated). The features I use the most is the toolbar on every monitor, moving full screen windows from 1 monitor to the next (without making it not fullscreen as windows requires) and the spanning desktop background. Im sure there are other programs available but work paid for this one, so this is what I use.