Well if you have timing issues, a metronome can help out, but if you are on a *very* tight budget, as in zip - get Audacity and use click-tracks, this is the cheapest alternative to a metronome that I know of, since it comes free.
Good thing is also that you can use the same clicktrack independently, so if you are collaborating via the web, your stuff should be in sych, as long as it is in synch with the clicktrack you agree on.
Demo:
Download link:
http://audacity.sourceforge.net/download/?lang=nl