If your club has a web page, add a link to a signup page, which you can construct easily using Google docs. To view the signups, I just log into Google Docs and I get a spreadsheet with the names, email addresses, and phone numbers.
We added one to our site a few months ago, the response has been super! It also gives you a way to to contact the prospective hams and help them along while waiting for, and after, the class.
EchoLink, IRLP, Allstar and DSTAR linking - adding interest to repeaters worldwide 24X7