The official site:
http://www.linkinpark.com/

Some good fan sites:
Linkin Park Fans: http://www.lpfan.com

Linkin Park Web: http://www.linkinparkweb.com/

Linkin Park Network: http://www.linkinpark-network.com/

Push Me Away: http://www.Pushmeaway.com

Linkin Park Factory: http://www.linkinparkfactory.cjb.net

Linkin Park Inside: http://www.LinkinParkInside.com

Mr.Hahn:http://papercut.wo.to/