I’ve been playing fantasy baseball since 1996, but not of the roto variety. I play a simulation game run by http://www.scoresheet.com, and I think it is the closest game to actually running a baseball team. After you draft the team you set a lineup (batting order against righties and lefties, pinch-hitters, who you want to steel, etc) as well as your rotation and bull pen usage (how quickly you want your starters removed from the game, the order you want to use your relievers, whether you want to use a closer etc), and then based on the baseball games of the previous week, Scoresheet simulates 6 or 7 games against other owners in your league. To win the league you have to win enough games to get to the playoffs and then win the playoffs (and not have the most counting stats). Once you receive the games for the week you can see the boxscores or use a graphical interface to view the game at bat by at bat (like the casts on the espn website).
Take a look at the Scoresheet website and see if it interests you. Most people that try it don’t go back to roto (I haven’t), but of course you can do both : ).
I am running a set of one-year leagues where performance each year determines your rating and league placement in following years. I am looking for owners to form a 4th American League league (we have 3 NL leagues drafting now, and the AL leagues start drafting on Feb 29th). The draft is done a pick at a time and you can get more information on that at http://www.sofyl.com. The cost for a team is $84 (minus $15 for a first time owner) + $4 per lineup/pitching lineup change (so it will probably run you $90-$110) for one year. The cost is paid to Scoresheet, I am just another customer who helps to run leagues. They have been doing this since the late 1980s and run hundreds of leagues every year.
Let me know if you are interested, and if you have questions you can e-mail (mailto:firstname.lastname@example.org)