I've spent a lot of time working with hook_form_alter() functions to modify forms, but the other day I was stumped by a simple problem. I needed to have two submit buttons on a form. By default, in the latest branch of Webform, you can change the text label on the default submit button for a webform. If you take a look at the screenshot on the right, you'll see what my demo form looks like. The "Request More Information" button is the default submit button.
Webform is an amazing module. Thankfully, you can extend it to make it even more helpful. We've had a lot of clients that offer a "Join Our Mailing List" type of functionality on their sites. These forms are typically one or two fields (email and name, usually) and are for anonymous users. We use Campaign Monitor for most clients.