The way the Call Log works is crazy. Delete one entry, or delete everything. – Not any more!!!
Here’s the initial version of an application to allow you to delete logs, based on a number of criteria. As it’s only version 0.1, it only supports deletion by Date. But there’s more to come.
http://www.anddev.org/prunelogs_-_manage_your_call_log-t3705.html