Need to create simple download form

I want to create a download form that has:

Combobox - holds a list of software demos to download
Email - the email to send out
Submit button


After the user chooses a software product, enters their email, then presses the Submit button, I want the download to start. I suspect through a Redirect URL that goes to a thank you page?

If someone has some html code already, that'd be great.

Thanks!