Tony,
Yes, a lot.
I play mostly at Poker Stars for their sit n go tournaments, and as for "UK" sites, I sometimes frequent William Hill, VC, Ladbrokes.....
Success is reasonable as I've been playing for a couple of years, but it depends what level you play at. One of my old school mates is a seasoned pro, with a WPT win under his belt, and he plays 300/600 - big money time!
Much prefer playing live, which I do at a couble of clubs in London, and a few reasonable price tourneys across the south of England.