There are a couple of ways to create your own form:
Easy-
embed a Google docs form - select "Create a custom form on your public site " from dropdown on this page.
Not so easy-
Create a contact list in public side of Sharepoint
Grab this solution to make it anonymously accessible: http://anonymous365.codeplex.com/
Add a data form web part of the list to a Sharepoint page (in Sharepoint Designer)
Embed it on a public site page using this generator
(The generator itself is actually an example of an embedded Sharepoint form)
Add a lot of css to the source page to hide all the Sharepointyness
Set alert on the list to email you when there are submissions if desired.