Some quick summaries:
POKERSTARS
The best tournamnet players are on Pokerstars. Even the low level SnGs are decent (but beatable). The ring games there are tougher than other sites, but they have many cash levels so that you can drop to the "fishy" .10/.20 limit if you want to hone your game. They also have added some lower limit SnGs if you bankroll is tight (like $2-20 player or something like that). SnGs use timed blind increases as well. If you intent to concentrate on strictly tournament play, then this is the place to play. The competition is better - so you will get better playing there.
They also have the best customer service out there.
Drawbacks - they do not offer many signup bonuses- or have an affiliate program offering incentives to open an account.
PARTYPOKER
Largest site on the net - with the fishiest players. Good cash games. OK tournament ones. The low level SnGs are BAD as they charge twice the vig as Stars ($5 + $1 vs $5+$.50). This makes them much harder to beat for a profit. Also, the structure for the SnGs are geared for a faster game. You only get 800 in chips to start with blinds rising every 10 hands.
They also have many bonuses and incentives. Make sure to use an affiliate (
pokersourceonline is a good one) and you can get extra "stuff". Several members here have used
PSO for a 300 piece nevada jacks chipset. The affiliates are in addition to the site bonusts, so you get a double incentive.
PACIFIC
Very soft low limit games (at least uup to 3/6). No multitabling (playing more than one table at once) helps limit the sharks at any given table. Outdated software and interface give it a clunky look. Decent SnG games and tournaments. The software is BUGGY. Many players do not play there for this reason alone. Random disconnects and freezes hapen - sometimes often. This is usually linked to your hardware setup, so your experience may be different. Me- I have some 2-3 hour sessions with no issues. Sometimes, I have 2-3 missed hands in a half hours time due to random problems. For me, the soft games definately make up for it.
They also offer affiliate bonusses (
pokersourceonline).
Ultimatebet:
I have not played there much. Decent software and interface, and the player base is supposed to be better than average.
There are others - but you could do much worse than the ones listed above. Party and Stars are the two biggest - and the most "established" (they are the least likely to dissappear anytime soon). UB may be good for you as well, since you are already used to the interface.
If you want to play tournaments (and the CT weekly game), start at stars. If you are looking for softer games - Party.
Some blantant reality here. Make sure you are playing with money that you are not afraid to lose. I will not sugarcoat this, your first deposit will most lilely be used to line the pockets of other players. Playing for fun vs real money are two entirely different ballgames. If you have 100 or 200 thay you are willing to LOSE, give it a shot. Do not risk any cash that you need for other things. This will help you play relaxed, which should hopefully help you to win. $200 will give you ~ 36 $5 SnGs which is a lot of cardplaying.
Also, check out a book or two from the library. Discussions here are great for learning, but a good solid knowlegde base helps you to pull more from the discussions. A great first book would be Sklansky, Theory of Poker. OK, kind of reads like stereo instructions, but has tons of useful knowledge.
Where oh where to play? 
. I have read Slansky, Harrington, etc and played with my online group. While they tend to be a bit conservitive the level of play is fairly high. I'lll take it easy to start with, and decide if it is something that I want to stick with before getting very far into it.
Linear Mode
