for Starters...

Jack Johnson's Official Site : http://www.jackjohnsonmusic.com
Jack Johnson Fan Site by Zam and Zaboomafoo : http://www.jackjohnsonmusic.net
The first fan site i knew of on Jack (some other lyrics and tabs here) : http://people.ne.mediaone.net/jrkoosh/jack/main.htm

and then some... (other sites i visit)

Ben Harper's Official Site : http://www.benharper.net
Ben Harper site by ME : http://www.geocities.com/jais_blues/pages/ben/index.html
John Butler Trio Official Site : http://www.johnbutlertrio.com
That's about all for now... email me if you think something else belongs here that i have forgotten (ie it s somehow related and whatever) 

Other than that i would normally jut steal the links other JJ pages have compiled.. but i will put off the blatant plaguerism for when this site is fully functional...