The TODO list can be found on Trac for wp-plugins.org:
http://jacob.steenhagen.us/bugs/buglist.cgi?product=Upcoming+Events&resolution=---

New ideas as well as bug reports can be filed in my Bugzilla install at http://jacob.steenhagen.us/bugs/

Target are, of course, subject to change and future versions will probably
have more features in them than just what's on the list.