play money is very very different from the real thing. stay away from it in general unless you need to get a feel for the software or how good odds
are on hands (ie how often does your flush draw hit?)
aren't too horribly far from micro stakes tournaments, especially if you can get past the first hour or so. It isn't a bad way to learn MTT play, but it will teach you some bad habits along the way as well. if you play like that in higher stake ones you will get eaten alive, but it is a good first step to start and learn basics (tight beginning, loose later, position etc).
most of the US sites feel about the same to me as far as softness/where to learn best, so i don't really have any recommendations here.