If you're looking to do something just for yourself, have you looked at something simple like Google Calendar?

I always try and recommend getting your org onto Google Apps for this specific purpose. You can set appointments for other people, invite to meetings, etc. Sign up here: http://google.com/apps

Of course, there's the gold standard in Basecamp (http://basecamphq.com). We use it at Monk and it keeps all of us on the same page. Very helpful. Very useful.

Lastly, I've had mixed opinions about using Action Method Online (http://actionmethod.com). A fantastic analog utility, but I'm not crazy about their digital offerings. That said, I know many teams live and die by this web app.

Hope that helps. Good luck!