Forums

I did a trawl of the various forums here are a few decent threads.

http://www.guildwars2forum.com/threads/4433-Guardians-too-god-damn-OP

http://www.guildwars2guru.com/topic/47278-tome-of-conquest-your-guardian-competitive-pvp-guide/

http://www.guildwars2guru.com/topic/47104-xirrins-guardian-pvp-compendium/

http://www.guildwars2guru.com/topic/34879-guardian-videos-post-her

Retaliation:

http://www.guildwars2guru.com/topic/48391-defensively-offensive/

http://www.guildwars2forum.com/threads/6263-Ultimate-Video-Guide-Compilation-for-Guardian