I just posted a new version of PhoneLog for Blackberry, you can download the latest retail version from http://www.mobihand.com/product.asp?id=28638.  This version adds the ability to enable/disable logging for specified days of the week and has an option to prompt whether or not to log completed phone calls (missed calls are still logged, since you may not be available to answer the prompt).  I also made some under-the-hood changes that will enable me to make a significant overhaul of the functionality for the next major release.