Duel Screen Gaming, & TWO Screen in ONE?

First off, This is my Spec:

Vista Premium 32bit
XFX 680i mobo
Intel E6850 C2D @3.0ghz (Water-cool)
1000 watt PSU
350gb Raptor 10k Raid 0
150gb x2 Raptor 10k
4gb Ballstix Ram
X-Fi Champion Fatality
x2 512mb XFX 8800GT Alpha Dog Edition in SLI
Z-5500 5.1 Speaker
3ms 24" Gateway FHD2400 w/hdmi
6ms 24" Dell Ultrasharp 2408

Second:
I've NEVER done this before.
I've try to do educate myself a little bit. (Mirror mode and what not)

Ok so Here's my question.
I know some game support duel screen. (World In conflict, etc...)
And some game support SLI.
So...

-How do I use two monitor as ONE BIG SCREEN for an older game that does not has the duel monitor option? (Oblivion, Crysis, COD4, or CS:S)

-If I have TWO 8800gt in SLI, does duel monitor benefits me?
I've read that I must "DISABLE" SLI" to even use TWO monitor.
So is my SLI set useless to me then?

-Also sometimes I'll play in one screen and read tomshardware forum in the next screen.
Does my SLI setup prevent me from doing that?

-Can I plug each monitor to each card?
Or I can't do that because one card will be disable anyway.

Sorry in advance if this is the wrong thread. As I think it sorta goes into LCD & Gaming as well.