http://wiikii.darkain.com/wiki/VC_Notification
Pretty cool. You just add the e-mail address to your Wii address book, and you'll get an e-mail when VC is updated. I signed up and it works great- I got the e-mail after the update occured, but it was still same-day. Very convenient if you're waiting for that certain title and don't want to constantly be loading up the shop channel.