This is a free, handy little menu bar calendar I have been using for some time now:
There is a new version out and it now has iCal support! Just click on the date and it brings up that day in iCal. It also shows the date in the menu bar (you can even select an iCal icon in the prefs). I think it automatically installs as a startup item. Works great in Panther, I haven't tried it in Jaguar but should work.