My site (see sig) has some tips on playing poker, just the same as various other sites around - there's plenty of info online if you look for it. The best way to learn how to play poker is to read through some rules, sign up to one of the sites, and then play on the play money tables for a while. This will get you used to the interface and the game itself.
Bear in mind, though, that generally the players will be ridiculously loose, so winning on those tables is little indication as to being able to win on a
real money table.
Once you are comfortable with the game and the interface, then start developing your strategy (I'd recommend reading something like Super System, or at least learning a system like the Hutchison Points Counting sytsems, which you can google for), and when you can consistently play to a strategy, then either consider starting on the lowest stakes tables, or get your first stake amount by playing
freerolls - once you play well enough to place in the money on a freeroll you're hopefully good enough to build up that initial win amount to something more substantial).