A while ago, I created a small Java tool which runs on my computer at login time, checks my address database for birthdays and displays the information. At that time, I used ABC as address manager in a local install, and the reminder got its data from the underlying MySQL database. Then I moved on and bought a PalmOne Treo, so my ABC install and my old birthday checker slightly got out of sync. Now I have rewritten the reminder application to take its data from my synchronized Palm database, and here it is! The library functions of jSyncManager made it a lot easier.
Attention: As I was not satisfied with the built-in birthday field, I used the first custom field and NOT the field "birthday"! Sometimes I don't know the year, but in the standard birthday field, I would be forced to enter one. Plus when I generate birthday markers for the whole year using Feiertage for Palm OS this doesn't matter anyway - it can use any field.
There is no release of this software right now, but you can obtain the source code easily via Subversion (SVN). If you have a UNIX-like OS, SVN is possibly already installed. In this case execute the following command in the directory where you want the sources to go to:
svn co http://svn.zephyrsoft.org/svn/productivitytool/trunk productivitytool
If you are running a different OS, refer to your SVN client's manual (list of SVN client programs).