I'm interested to help with this and during my Christmas break would be the best time
for me to help out. Who else is into natural language?

take a look at this project http://bongo-project.org/Main_Page I think they have 
some of the logic done for the natural language parsing to appointments.

This library also looks promising http://code.google.com/p/parsedatetime/ . 

Incidentally, Jon Udell was looking for something similar. The comments to his post
http://blog.jonudell.net/2008/04/02/parsing-human-written-date-and-time-information/
reference iwantsandy, parsedatetime.

I hadn't clicked that sandy was probably written in Ruby. The Chronic library is also
referenced: http://chronic.rubyforge.org/ If parsedatetime doesn't cut it, would a
python port of Chronic be a reasonable approach?

parsedateformat being used to parse dates. Timezones respected.

Now in testing.