I've been using org-mode for the last few months to do my time tracking and it has worked out pretty well. You can use "clock tables" to get a report of all of the logged time within a certain window (e.g. february)
Works great, especially if you're using emacs for writing code too.
Look here at http://orgmode.org/ and http://doc.norang.ca/org-mode.html for brief and in-depth use information.
Good luck.