A while ago we had a consultant out here. He saw this SSL probe that I created and seemed to think it was worth posting. It's based on code from http://lopsa.org/node/1547. It can handle HTTPS, IMAPS, LDAPS, SMTP and even cert file downloads. It supports QoS so that you can display all of your SSL expirations on a dashboard. I think it's pretty slick. Hopefully someone else will like it.
It requires openssl which can be downloaded from http://gnuwin32.sourceforge.net/packages/openssl.htm.
It also requires perl. I use 5.10 from http://www.activestate.com/activeperl.