1000 kills with it ,tactical knife doesn't count.
no. for prestiging you only unlock new titles/emblems extra custom classes and a new symbol.
if u have ps3 add ownupwnu69 for mw2
Nope - just another class addition, challenges and titles/emblems.
They can be found at the Call of Duty wikia. A link has been added under related links
You get the ability to unlock more titles, emblems and challenges even for guns The bad thing is you'll lose all your camos, guns and xp
Well, it depends. You only get titles and emblems if you do certain things. For example, you use stopping power a lot. Finally you get the emblem for it. You could just get a few emblems and still be a level 70. It depends on what you do.
http://callofduty.wikia.com/wiki/Callsigns
50 multi-kills with claymores, frags, rpg, and/or c4
Yes you lose everything but titles and emblems
go to http://callofduty.wikia.com/wiki/Callsigns
By getting into a tenth prestige lobby.
challenges and stuff