This seems really good! I've been using 30boxes for awhile, and that's been great - but I think Googlecal might be even better. Actually, the one thing that definitely makes it best for me is that it allows date entry in European style - i.e. 31/12 instead of 12/31 - a very simple tweak, but it makes all the difference to usability for me. Backpack is going to have a calendar soon, which will probably also be worth a look.