regexp help

i'm try to isolate the date beteween <stopdate> and </stopdate> in an
xml file with lines that look like this (all one line):

<item><taskuid>66764377.1</taskuid><task>Get new email from
0.0</task><result>cancelled</result><message>Server 0.0 (127.0.0.1):
The connection was refused by the server.</message><startdate>Sat, 11
Feb 2006 17:39:37 -0500</startdate><stopdate>Sat, 11 Feb 2006 17:39:50
-0500</stopdate></item>

i've been using redet to test my attempts, but i usually get one of
two results, either not match, or i match the entire string.

i thought this would work:

<stopdate>[a-zA-Z0-9]</stopdate>

but it matches the entire string.

any help appreciated. i've got this nagging feeling i'm missing
something simple (as per usual when i get stumped).
http://home.cogeco.ca/~tsummerfelt1
telnet://ventedspleen.dyndns.org
Received on Sun Apr 30 02:19:12 2006