FYI: After the first wave of 2500 hackers have been banned since IW's little twitter account things are looking good on MW2. The nice thing about vac bans is that they are not instant from what I've read. I personally haven't encountered one cheater yet in MW2. It's amazing. If you do need to report a cheater however I came across this in an article on how to report a cheater on steam:
"During or after you've played the game with the hacker open Steam. Under the players menu, you can go to previous game. Under that menu click on the player who is hacking and open their Steam ID page.
On the top right corner of the Steam ID page you are able to "report violation". If somebody is suspected of hacking I will put in the comments "suspect of hacking - {whatever hack}". If it's something confirmed, I will put "Confirmed hack - {whatever hack}".
I haven't done done this yet as I haven't came across a cheater but if you do, there you go. Nice to see IW and vac working hard on getting these cheaters.
"During or after you've played the game with the hacker open Steam. Under the players menu, you can go to previous game. Under that menu click on the player who is hacking and open their Steam ID page.
On the top right corner of the Steam ID page you are able to "report violation". If somebody is suspected of hacking I will put in the comments "suspect of hacking - {whatever hack}". If it's something confirmed, I will put "Confirmed hack - {whatever hack}".
I haven't done done this yet as I haven't came across a cheater but if you do, there you go. Nice to see IW and vac working hard on getting these cheaters.