For all COD4 TWL players it is now required to have and run the XRAY anticheating program while you play COD4.

The link to XRAY gaming website is:
http://www.xraygaming.com

The link to the download page is:
http://www.xraygaming.com/index.php?pageid=xac-download

You will need to REGISTER first to download the program.

Here is some information about the X-Ray (taken from the X-RAY gaming "About" page):

What is X-ray Anti-Cheat?
X-ray Anti-Cheat is a program designed to catch and eliminate cheaters in online games. X-ray is a client-side application, running on your machine and offering protection to you and your team-mates in online leagues and tournaments. It allows you to check for cheaters in any match you have played by viewing screenshots of their matches on xraygaming.com.

How does X-Ray work?
X-ray uses state-of-the-art methods to protect you and your online gaming experience. It will periodically take screenshots of what you are seeing in-game, and will scan for known cheats and bad processes in the background to help with cheat detection. When you are finished playing your game, X-ray will upload these screenshots to our servers, where our experienced admin team and massive userbase will help catch cheaters by reviewing screenshots and 'flagging' them if they appear suspicious.

If found and proven to be cheating, the users' game identifier (either a Steam ID, a GUID or CD-Key) is banned from all group sites and any partner leagues, ensuring you play in a cheat-free and safe environment.

Where did X-Ray come from?
X-ray is based on the work of two admins from the UK's most popular gaming league, Enemy Down, Ed Scutt & Crispin Wright. Bolstered by the resources of parent company TNWA, X-ray is now the premiere client-side anti-cheat, boasting monumental hardware and systems support to ensure the service is always available to help put a stop to cheating. X-ray Anti-Cheat is fully Vista and XP compatible, and runs with almost all games these two operating systems support.

Who can use X-Ray?
Unlike other anti-cheat software that either limits you to its own servers or forces you to pay a subscription charge, X-ray Anti-Cheat is completely free to download and use in any league or event of your choice. That means if you organise LANs, online events or tournaments you can partner with xraygaming.com to ensure your event is completely cheat-free. With our new API features, you can even embed the information on your site for the benefit of your members. For more information on how X-ray can protect the integrity of your events, contact us.