Check out Bass Player Mag
www.bassplayer.com and do a search on George Porter. He was recently interviewed and below is the lowdown on his gear. I agree GPJ is a groovin' SOB. He recently was on Austin City Limits with the New Orleans Social Club (great CD too). Also check out the Deepest End CD/DVD set from Gov't Mule. GPJ along with a slew of great bassist are on the set in a tribute to Allen Woody.
Gear
Bass Fender Precision Bass-1970 Precision body with a circa-1965 Precision neck
Rig Ampeg SVT-4PRO head; Ampeg cabinet-SVT-610HLF (home) or SVT-810E (road); Shure UC14 wireless system; Morley ABY Selector/Combiner; Whirlwind IMP 2 DI; Boss TU-12H Chromatic Tuner
Effects EBS UniChorus, EBS BassIQ envelope filter, EBS OctaBass
Strings D'Addario XL Nickel Round Wound Long Scale (.055, .065, .085, .105)