you can get mac app update from
www.macupdate.com or
www.versiontracker.com
you can get cool wallpeprs from
www.interfacelift.com
Skype is best for video chat with your friends across different platforms
Don't forget to calibrate your battery when you get it.
You can take screenshot of full desktop by press shift+cmd(apple key)+3, or you can select part of desktop by pressing shift+cmd+4
Reset PRAM is pressing cmd+option+P+R when computer boot
You can reassign F* keys to behave as F8 rather than function keys if you need from system preferences
You might want to check preferences and enable expose active corners.
You can get much cheaper RAMs in case you want to update from
www.newegg.com
and yes, I also recommend firefox 3 beta 5, unless firefox 3 RC1 will be out before you receive your MBP, as a beta, its more stable than firefox 2 for many users. Its more optimized for mac and you should try it out for sure.
Finally.
Search google for your questions.