Ah, Corinne.
Welcome to a fascinating journey!
You're asking for, specifically, a readable book for guidance on playing online poker. It sounds like you're playing some cash as well as tournament poker, and the first thing to say is that you will face different challenges in these two disciplines. I should mention that online has some significant differences from live as well, but we can cover that when you decide to move into the live arena.
I actually really liked Moorman's Book of Poker. Chris Moorman is a top UK pro with tons of live and online experience and cashes. This book is very approachable and will give you a good insight into the decisions he makes and the logic that underlies the decision making process.
Although largely based on his live experience, I would heartily recommend Harrington on Hold 'Em as a definitive work on tournament poker. Depending on your book buying budget, and learning appetite, I might also recommend Phil Gordon's Little Green Book which is arranged in bite-size snippets of information which you can dip in and out of to your heart's content.
For good tips on basic play, I would bear in mind that the relationship between the skill set of your online opponents and the cost of participation can be described as an S-Curve. By which I mean that the typical participants in a $1/$2 cash game will be more than 10 times better than those in a $0.10/$0.20 game but less than 10 times worse than those in a $10/$20 game. Understand your opponents and don't necessarily carry a working strategy from one stake into a higher (or lower) stake game.
I would also recommend watching as much televised poker as you can stomach. If you have a smart TV, you can pick up all of the previous ESPN World Series broadcasts, and the Channel 4 EPT programs. Since you get to see the hole cards on all of these, they can be great learning tools for what the pros will do in spots that you will, at some point, face in your poker playing career. When watching highlight shows, however, bear in mind that you are seeing 1 hour of highlights edited down from 8 hours across 5 or more tables. There really aren't that many set over set, or flush over straight hands in a typical session!
Here in the UK, as well as Virgin where you're already playing, there are plenty of other sites available. I play on Pokerstars, where I recognise that I face a skilled group of opponents, but also on Party Poker, where there is a strong skill set but a higher proportion of more inexperienced players.
Read the books. Play LOTS of hands at low stakes. Learn to meld the book learning with your natural, preferred style of play before you step up in stakes. Go to Vegas and win the World Series. Easy!
See you at the final table,
Bri
