OK, so
you can play alterIwnet's special ops with your friend, i havent tried it but according to some people it does work work,follow these steps:
Download the file attached below
1. Copy TeknoGods_MW2SP.exe and TeknoMW2.dll to your game folder.
2. Make a shortcut to TeknoGods_MW2SP.exe and add --ip=<host ip> after
Example TeknoGods_MW2SP --ip=10.0.0.1
Usage For Server
1. Copy TeknoGods_MW2SP.exe and TeknoMW2.dll to your game folder.
2. Run game from TeknoGods_MW2SP.exe
In game use for server
1. Goto Spec Ops
2. Click Two Player Online
3. Host the game and wait in lobby.
In game use for client
1. Simply press F12 to connect
(sorry for pasting big chunk out of another forum but this was the ultimate way to explain how to do this )
If it still doesn't work then you have to download NTAuthoritie's iw4sp.exe fix.
Also another way you could try is play SO with your friend through xFire.
Oh, and you have to download these files on both computer if u want SO to work.
TeknoMW2_Hotfix.rar - Jotti's malware scan
VirusTotal - Free Online Virus, Malware and URL Scanner
These viruses are fake positives, like cracks and stuff.