If you need a form, particularly one that saves data into a spreadsheet, Forms in Google Docs is worth looking into. Simple and quick, it allows you to create forms for storing spreadsheet data like addresses, quiz answers, or create a simple guestbook.
The link to the form is available on the creation page, there is an email option, or you can embed it in a page of your choosing. It does have some simple themes for sprucing up the form and multiple options for input. If the form is new, Google Docs will add a spreadsheet for you.
You can't retrieve the information through a form, so users can't edit previously submitted responses without access to the form. You can't control access to the form itself as far as I can see so one thing to consider is avoiding abuse if it is forwarded to the wrong people. One simple workaround to filter the unwanted responses might be to include a code in your email or link. When the users enter this code in form it will go into a column in the spreadsheet. The spreadsheet can be sorted by this column and then entries with incorrect or missing responses can be deleted.
To create a form in Google Docs simply click New->Form.
A simple form and the spreadsheet created for it.

This tutorial is also available at http://tmoodini.com/tutorials/googledocsforms.html