LBP Main site/Blog:
http://littlebigplanet.us.playstation.com/

Media Molecule (Dev site):
http://www.mediamolecule.com/

Unofficial LBP Blog:
http://www.lbpblog.com/

LittleBigPlanet Galaxy:
http://www.littlebigplanetgalaxy.com/

Will add others upon suggestions. I don't know of many fan sites.