This looks to be a Google Docs form (used for making surveys), it just has a single question which is a "paragraph text" field. It shouldn't take long to do the same thing for yourself.
Have a look at this help topic for details on making a form.
That worked fairly well for me; I have what I think is a working feedback form. (I mostly copied lukeprog's wording, but omitting the parts about SIAI and hopefully wording it more friendly.)
The tricky part was figuring out how to set up email notifications: you have to go to the spreadsheet version of the form, click on Tools->Notifications and work from there.
Time and time again, honest feedback has improved my life. I have sought it out on many specific occasions, but now I have a static, anonymous way for people to give me feedback — for any reason, at any time.
You can give me feedback on my personality, my conduct, or the organization for which I work by following this link right here.
Thank you. I apologize for making a discussion post that is all about me.
I operate by Crocker's Rules.