If a player transfers to another school, the NCAA mandates that she sit out one year. Some, but not all, conferences tack on another year if the player transfers within the conference, therefore the player would have to sit out two years in certain circumstances. A coach can release the player unconditionally and therefore waive the second year, as Geno did when Kia Wright left UConn to go to St. John's (the NYC kid was very homesick).
If a girl is granted a release, she sits out the NCAA mandated year but is on scholarship and can practice with the team. If she is not granted a release, she may leave the school but must sit out the year without a scholarship. I'm not sure what happens to the second year if she transfers within a conference - I think each conference has its own rules.
As far as I know, c
urrent rules only allow students whose schools have received the death penalty to transfer to another Div I school and play immediately (I could be wrong on this, though). If a player goes to a Div II or III school, she
can play right away. The NCAA is
contemplating a hardship exception but it isn't in effect yet.
I hope that helps.