After my minor gripe that the iPhone's calendar app displays the proper date on its icon, even though Mac OS X's still doesn't, a few readers directed me towards iConiCal. Basically, all iConiCal does is start up up iCal to update its icon, then it quits both iCal and itself so you don't have extra apps eating up system resources, but you also gain an iCal Dock icon that keeps you up to date. iConiCal also gives you some icon customization options, offering two alternative colors for iCal's icon both in its dormant state and after it is updated. Of course, this app also has a 'start at login' option so your iCal icon can get set right when you log in or start up, so you won't have to think about it for the remainder of your session. For anyone clamoring to have an up-to-date iCal icon and those who aren't up for adding the date to their menubar by tweaking the Date & Time System Preferences pane, iConiCal sounds like a fine solution.
iConiCal is donationware available from BlockSoft.