The AWK script converts .vcs files into XAPIA format files that can then
be dragged and dropped on the Calendar icon of the front panel to
insert an appointment in the CDE calendar.

Initial version:

The program has some limitations. For the moment, it ignores ToDo items
and only converts appointment items. Also, it has to convert 
appointments that extend on more than a single day (such as holidays) 
into daily repeats
and to transform "UNTIL=" repetitions into a number of repetition.
This is done by using an average duration of 30.44 days for a month
and 365.25 days for a year instead of using the correct duration for
leap years and for months. So the duration of an appointment can
be sometimes calculated incorrectly.
Appointments in the local time are not handled very well. The script
assumes that the local time is UTC+1.

It is released under MIT license.
      http://opensource.org/licenses/MIT

Better programs (in Perl) to interact with dtcm by Adam Stein are available at:
http://www.csh.rit.edu/~adam/Progs/programs.html
They require to install the Calendar-CSA-0.8.tar.gz Perl libraries from CPAN.


Christian Pélissier  has posted a dtksh program in a french
email list on Solaris x86 that also does the vcal to XAPIA
conversion. His message is archived here:
http://www.mail-archive.com/solaris_fr@x86.sun.com/msg02388.html

Version 2.2.4:

- improvements to the script to handle repeating appointments.
  The script supports appointments that repeat every N week/month/days.
- easter.awk: script that creates appointments for (Roman Catholic)
  Easter, Ascension Day and Whit Sunday.

Current version:

- added support for ToDo items.
- added support for numeric timezones (TZ:+NN or TZ:-NN).