Doodle replacement

Hi,

I'd like to say that I'm open to using Sharepoint 2007 or Microsoft Outlook 2010 to accomplish my goal. I'll explain my problem:

I have to schedule several 3 hour blocks to train people. Only 6 people can train at a time and there are several sessions that they can choose from. I was going to create a Doodle and have a limit set up on each event so that no more than 6 could register.

We want to keep this in-house so using Doodle won't be ideal.

Any ideas on how I can set this up?

Thanks,
Robert