It's free. Try it. If you don't know what it is, check out this web site, it describes it very well in just a few words. http://bsdo4ever.tripod.com/
If you already know what it is then let me give you this. We are using MVP Baseball 2004 to SIM. If you want to join, email mailto:email@example.com.
All teams are still available, because we are waiting on enough GM's for a complete league, and then we will hold a lottery to randomly assign teams to the GM.
Check it out.