Not sure where you are located but if you are not in the US, you have many choices. Pokerstars is the "big" game online but there are a few other sites that are starting up.
Really if you want an easy start, I would suggest going with Bodog. The competition there seems weaker than Pokerstars and it is an SBR sponsored site so if you deposit $200, you can go PRO here at SBR.
Otherwise, I would look around at the different options and chose for yourself.
Lastly, I suggest you sign up for rakeback, the two sites I use is raketherake and bankrollgiant.