Touch Calendar Free
A really neat idea–a variation on the standard calendar app, that lets you, by touch, zoom in on your calendar as necessary, rather than having to flip through different views to see details.
A very customizable calendar widget that works with multiple calendar applications and can show events from multiple calendars.
Web-based appointment scheduling–kind of an Open Table for other kinds of businesses. You can search for hair salons, for example, in your area that will accept appointments through this service.
Avoid– it’s both ugly and minimally functional, as well as ad-supported.
Schedule when your phone should go silent so you don’t forget and have it go off at an inopportune moment!