JACQUEG  I downloaded this software, paid the fee, and used it happily for about a month. Then I downloaded the update.

BIG MISTAKE. My MacBook, running the latest version of Leopard, started acting like a WIndoze machine inflicted with an overload of spyware. I had to restart in safe mode to uninstall the software. Wondering whether the file had become corrupted, I removed iDeskCal and downloaded anew. No fluke, my MacBook is unusable with this software installed.

The company has not responded to my request for assistance. Even if your computer handles this software OK, you should think twice about people who do not respond to their paid-up customers.  
(Version 2.2)