Current version of gMFSK is 0.6. You can download it here.

gmfsk-0.6.tar.gz

These RPM's are built on my Red Hat 9 box with Hamlib 1.2.0

gmfsk-0.6-1.src.rpm
gmfsk-0.6-1.i386.rpm
gmfsk-debuginfo-0.6-1.i386.rpm

A prerelease version of the forthcoming version 0.7 can be donwloaded here. While I do encourage people to test it, there might be some rough edges in it, so be warned...

gmfsk-0.7pre1.tar.gz

All versions of gMFSK can also be downloaded from Hessu's server:

http://he.fi/pub/ham/unix/linux/hfmodems/

The directory contains source code in tar.gz format and both source and binary RPM's. The binary RPM's are generally compiled on the latest version of Red Hat linux that was available at the time...

Many Linux distributions already include gMFSK in their collection of software. There is also a FreeBSD port available.