I saw Bil Simser's reply that one could use the Form Web Part, but I was wondering if anyone had any tips on how to easily let users create email forms on their pages.  I'm thinking of a web part that one could plop down somewhere and easily customize with their own forms, and have it work with the built-in email service.

I loaded up the Form web part and saw that it was some basic html at first, as follows:

<div onkeydown="BLOCKED SCRIPTif (event.keyCode == 13) _SFSUBMIT_"><input type="text" name="T1"/><input type="button" value="Go" onclick="BLOCKED SCRIPT_SFSUBMIT_"/></div>

I guess what I'm looking for is some concrete examples of what code can go here in order to let people send email with WSS and/or SPS.