In my work for the Westside Mothers of Preschoolers, I have ran across a cool tool that might be of use to you.

It is called Mollyguard. On this website you can set up an event, specifying not only the date and time, but the capacity that you can accomodate and the price of the event. You can have multiple "ticket types" with different prices and can collect credit cards via PayPal. You can track your registrations and ticket sales. The basic (free) service is quite robust and they offer a premium service for those who want to do their own branded look and feel.

I have found it easy to use and just what we needed. We are going to use it to allow people to register their children for childcare provided during our meetings. We may also use it for registration for special events where capacity is limited or we want to collect fees ahead of time. This tool really starts where Evite ends.