condor cycles - quite possibly the best bike shop in London. Only down side is that it's a VERY popular store.
Sheldon Brown, Harris cyclery - best website, ever.
Park tools repair/tools guide - so even people like me can get instruction on bike repairs and the correct tools for the job.
LCC and CTC - not for profit cycling groups whose actions are as well thought out and effective as their campaigns. LCC has the lead on the monthly magazine but only by half a length.