Here is the link:
http://n.ethz.ch/student/mmoeller/fms/index_e.html

It is very good. It is also free.

If you are not to bad with a soldering iron (actually, I'm am pretty bad and I made it), you can make an interface to your transmitter's buddy box hookup to use your transmitter to run it. Or you can buy one from various sources $30 - $50 or so).

FMS will teach you the basics of flying and give you a feel for how certain models fly.

G2 is really good, is a bit more expensive than free, and has multiplayer support. I think it is a bit easier to customize planes and fields for G2.

Planes taxi good on G2, not so good on FMS.

The sound of balsa breaking into little pieces is more realistic in G2.