LinuxMusicians

at http://linux-sound.org/ you can find the section musician utilities.

Do you use one of them?

I have Solfege installed and a metronome fmit, which doesn't work very well for me...

I like to try Jazz Improvisation Primer http://www.outsideshore.com/primer/primer/

but the java file didn't work very well too...

http://das.nasophon.de/klick/

klick is an advanced command-line based metronome for JACK. It allows you to define complex tempo maps for entire songs or performances.

Features:
Support for tempo maps, including arbitrary meters, tempo changes, accelerando/ritardando and more.
Three built-in sounds (borrowed from Ardour, GTick and FreePats), plus ability to load your own samples.
JACK transport sync support (master/slave).
No GUI ;)

qjacktuner to tune the guitar

http://developer.berlios.de/projects/qjacktuner/