From the TS FAQ at
http://www.microsoft.com/windowsserver2003/community/centers/terminal
/terminal_faq.asp
<quote>
Q. How do I use the Remote Desktop Web Connection?
A. First you must install Remote Desktop Web Connection. The
Installing Remote Desktop Web Connection in Windows XP (Q284931)
step-by-step article shows you how.
You use the Remote Desktop Web Connection the same way you use the
standard Remote Desktop Connection application. You enter in the
blank field the name of the remote computer you want to connect to
and then press the connect button.
To get to the page through Internet Explorer just enter
http://yourwebserver/tsweb/ in the address field, where
"yourwebserver" is the name of the computer on which you installed
the Remote Desktop Connection.
</quote>
You can download from this link:
http://www.microsoft.com/downloads/details.aspx?FamilyID=e2ff8fb5-
97ff-47bc-bacc-92283b52b310&DisplayLang=en