I once played poker online for maybe half a year while I was still a student. It was pretty good & easy money back then, until
- more and more people learnt about what costly mistakes to avoid.
- the online poker rooms increased their rake.
There wasn't much money to be made anymore, some exams had to be taken to finish my studies and so I quit playing poker online.
PokerStars was always a pleasant experience to deal with, but I cannot guarantee times haven't changed. You might want to check with this forum:
http://www.twoplustwo.com/ (navbar on the left, choose 'General Gambling - Internet' direct link:
http://forumserver.twoplustwo.com/postlist.php?Cat=&Board=inet ).
However if you don't neccessarily need to play poker for real money you also might want to have a look at Poker Academy (
http://www.poker-academy.com/ ). Their software is pretty strong a.i. for playing offline and they have an online room, where you can play for a fictional currency that cannot be replenished at insane rates and therefore makes people play somewhat more realistically.