All about BB's: http://www.sheldonbrown.com/bbsize.html

Same tool to install/remove. What tool that would be all depends on the specific BB.

I use anti-seize compound on the threads. Normally I use blue Loctite for everything, but due to the very large surface area of the BB threads, and the torque used on them, I am afraid Loctite would make things way too difficult to remove.

I use only cartridge-bearing BB's, (and hubs). Life is too short to waste time on the old stuff. I have one bike with an 11-year-old Shimano BB that is still rock solid and silky smooth.