I am just now picking up cod 4. I bought my ps3 in decmeber, and bought cod 5 from a reccomendation of the zombies thing. even before all the new maps..
But, because of MW2's impending release, Im gonna RENT cod 4 for a month, just to get used to the wepaons, characters, etc.

1.) what is the best killing wepaon in the game?
2.) what is the best mp mode to gain xp?
3.) what are several ways it differs from cod 5?

Thanks for all help!

Oh man, you ask some tough questions.

1) In my opinion, I really like the MP5, AK47 and the M16. They're really effective and end up helping a lot.

2) I like to play Search and Destroy or Headquarters and you can really rack up some points if you're good at it.

3)Umm, let's see, for one, it's called MODERN warfare. Big difference there. Also, there's no dogs in multiplayer. No CTF, which sucks btw. I can't really think of anything besides some of the obvious stuff. Modern weapons. Different maps. Stuff like that.

You can get a chopper instead.

Mp5, P90, Ak47, R700. Love those guns. Also, if you're used to the powerful sniper rifles of WaW, try the R700. Very similar to, say, the Mosin Nagant, in terms of stats.

hmm thanks everyone. the helicopter, is it similar to dogs? or is it like as soon as it comes you're screwed? any way to destroy it or something?
Wow, thats wierd. no CTF? what they hell were they thinking?!
thanks for the answers guys.

i think the helicopter is much better than dogs. you can destroy it yes.

It simply shoots machine guns and (sometimes) rockets down on players who aren't you. And a rocket launcher, noobtube, or a whole lotta bullets can bring it down quite easily. Also, the airstrike is slightly different from artillery, rather than a constant barrage of shells, 3 planes fly overhead, each dropping one group of bombs at once. Much easier to suprise people with.

oh okay. so like in Bf1943?

I have never played BF: 1943, but it seems likely that they are similar concepts.

oh okay. well, Im liking cod 4 now. too bad mw2 will be all dirffrent maps ill have to memorize agian.

Haha, that sucks. At least you're used to some of the weapons. Remember, Ak47 with double tap pwns!