The best of them all are Tmanager.
http://www.thumbmanager.com
Another good one is:
http://www.mdue.com/turbothumbs.html
I have a very simple one to $25.
That rotate them randomly with cron setting. There is a little more work with it, but it do the work.
I have a site with it on, it was setup very fast.
http://www.grannytgp.net (sorry for the exit) CTRL + F4 to close it.
You can contact me on icq 32677225