Betting Links has close to 200,000 links devoted entirely to sports betting and casino gambling. However, it is naturally not so easy to find and good quality on all links.
UK Gambling Resource
UK Gambling Resource is a guide to casinos, bingo, horseracing, betting, spread betting, poker rooms, gambling watchdogs and much more.
Wednesday Nite Poker Archive
Online gambling portal. Features news, various guides, tests and directory. The information is quite shallow and limited mostly to Boss Media casinos.
BestCasinos.co.uk is a British guide to online casinos and gambling, part of a clan of similar sites. The emphasis is on casinos in the UK. Features beginner's guide, directory, review, rules & strategy, links, etc. Very nice interface, easy to find. The information is a bit shallow, but accurate and un-biased.
AskGamblers is a large gambling directory. Browse online casinos, poker, sportsbook, bingo, lottery, backgammon, skill games and lots more.