Although there are several differences between freestyle and folkstyle, and more between Greco and folkstyle, a lot of the wrestling technique for all three styles remains pretty constant. Freestyle and Greco reward action more than folkstyle, in which control is more important.
With a background in folkstyle you will find it relatively easy to learn the differences in the styles, and these same differences will actually help you become a better folkstyle wrestler! The list of clubs that coach the Olympic styles can be found at
www.usawks.com/freestyle_clubs.htm.