There is always www.lcwo.net
Second Option: I installed WINE and run G4FON with Ubuntu.
It has a few glitches, but it works.
Morse Runner did not work for me with WINE/Ubuntu, but that doesn't mean it can't be done. My overall favorite is Morse Runner, by the way. (I run it on XP.)
There are other great programs as well, but I have not tried all of them on Ubuntu.