There are many ways to recruit participants for a remote research study from your website. (If you’re already confused, see this post for an introduction to live recruiting.)
Another option is to embed a form somewhere on your website that users can fill out to opt-in to your study. Here are a few examples of form tools you can use: the first one uses the Forms functionality in Google Docs, and the second is a standard Wufoo form.
Google Docs form:
Wufoo forms are basically the same, loading its responses into an online table (login required). As with Google forms, you can link to page that contains only the form.