When I Started playing bass guitar (many years ago!) I was used to use the web (that were exteremely poor respect to one we all know now) as a resource for technique exercises or tablature of my favourite songs. Don’t need to say that now is undoubtely a stronger resource: you can find masses of videos of your favourite bass player lessons on YouTube and millions of tablature wherever you look!
I’d like to advise some links which help me a lot in the past years:
ActiveBass: probably the largest bass players community. You will find technique exercise and lessons, users reviews, auction and a built-in metronome and tuner, so, once you’re in you got all you need 😉
Bass Tab Archive: when I found it I thought it was a miracle, an entire archive of tabsfor free!
Harmony Central: not only bass guitar, but all you can need about music and musical instruments infos you can find it there, surely the largest archive of news and reviews about all kind of instruments. You can find the bass section here.