Just play heaps of search and destroy. A standard kill is worth 500xp and a headshot is worth 1000xp. When you plant and defuse bombs you again gets 1000xp+ the match bonus. I got 170 00xp in one hour just by doing that.
Play Demolition, it gives you the most xp.
if u mean what level u have to be to prestige in mw2 the answer is level 70
to unlock the stinger missle in mw2 you must be level 30 or sergent major II
Reach Prestige 1 and Level 69.
Level 4
u have to level all the way up to level 70 and then go into barracks and select prestige mode.
Level 70, which is the level cap.
commander
Kill an enemy within ten seconds of tactically inserting 25 times.
Level 22.
you carnt do mw2 campain two player
in cod black ops there is a 15th prestige and in mw2 there is only 10 prestiges because to prestige in mw2 you have to get to level 70 but in black ops you only have to get to level 50 to prestige