http://www.teamfortress.com/meetyourmatch/faq/
Yay more info
Q: HOW DO I GET ACCESS TO COMPETITIVE MODE?
A: To gain access to Competitive Mode, you must have a Premium TF2 Account and a qualifying telephone number on Steam. Examples of a telephone number that does not qualify would be a Voice Over IP number (e.g. Skype) or a number linked to a VAC-banned account. (For more information about qualifying phone numbers, please visit the Steam FAQ.)
Q: WHY DO I NEED A PHONE NUMBER?
A: Associating a phone number with a Steam account helps ensure a greater degree of account security and player accountability, which reduces the likelihood of cheating and abuse.
Q: WHAT IF I CAN'T OR DON'T WANT TO PROVIDE A PHONE NUMBER?
A: If you are unable to associate a telephone number with your Steam account, you can purchase a lifetime Competitive Access Pass from the Mann Co. Store. When the Meet Your Match Update goes live, you will be able to buy the Pass at an introductory discount rate of $9.99.
Q: WHAT ARE COMPETITIVE MODE'S RULES AND RESTRICTIONS?
6v6
no class or weapon restrictions
no random criticals
no team changes
fixed shotgun spreads
for symmetrical Control Point maps, best-of-3 or best-of-5 (higher ranks only)
for Attack/Defense maps, stopwatch mode (fastest attacking team wins)