Just asking

any way to play mw2 with steam for free?

Yes, alter iw net.

But no, you won't be able to play with your friends that have bought the real mw2.

(You can add your games to steam that is not from steam, so you can use the chat system and so on in that game, and your friends will be able to see that you play it.)

The answer for your question easy:

NO, you can NOT play mw2 free for steam.