After spending a few more hours looking around the web, I tried the Discussion Boards on Apple's website -- I've never been there before. But apparently other people were experiencing similar problems after installing a particular version of the Cisco VPN Client. Which is what I installed about a month ago (and hadn't yet had the reason to use).
Uninstalled, restarted twice, problem gone. :) Woohoo! -Ry [EMAIL PROTECTED]