Hi, we didn't have on our roadmap to output timeslots as excel, but it would be a welcomed addition if you could deliver it to us.
We don't have much development documentation yet. I'm constantly struggling to find the time to write some development docs.
You can checkout the latest code (version 1.2) at the HEAD of sourceforge CVS repository. It is read only for the anonymous user. The command to checkout the code would be:
cvs -d :pserver:anonymous@opengoo.cvs.sourceforge.net:/cvsroot/opengoo checkout opengoo
Bare in mind that this is unstable code.