And if you want to use Perl instead of JavaScript, look at FormMail.pl
which is pretty flexible. Replace the normally hidden "recipient" field
with a SELECT like John suggested, and it should do what you want:
<form method=post action=/cgi-bin/FormMail.pl>
<input type=hidden name="subject" value="Class submission">
<input type=hidden name="redirect" value="manythanks.html">
<input type=hidden name="recipient" value="behr@math.niu.edu">
...
</form>
-- Eric Behr | NIU Mathematical Sciences | (815) 753 6727 behr@math.niu.edu | http://www.math.niu.edu/~behr/ | fax: 753 1112