How do I 'alt-tab' out of World of Warcraft to use Firefox?

Sort of self-explanatory. As other WoW players might know, use of a browser during play is often very useful. Wondering how to minimize the game while its running to let me do this.

On a somewhat separate note, I have a separate LCD monitor plugged into my MBP (my first dual-head setup and I'm loving it thusfar). Is it possible to have a web browser open on one screen and WoW on the other, with a key combo to switch between which one my mouse is active on? That would be quite cool.

Thanks for any help.

So simple! D'oh! Thanks, that does everything I wanted and more. Excellent.