Like I said before SBS 2003 doesn't allow the use of TS except for the admin using the /console session. However there is a simple way to circumvent this but you will end up only allowing 2 simultanious users (+ admin using /console). SBS 2003 is configured like this on purpose, MS offers SBS at a reasonable price with alot of features for a reason \:\) What they won't do is sell you CAL's for the TS on SBS 2003. They will tell you to buy 2003 Standard and setup TS on that.

SBS 2003 does contain Routing and Remote Access though so you can set up VPN's between the two domains.

100% separated networks... basically only thing that needs to be different is the DHCP scope and domain name.

Also you can do a really cheap solution if only 1 person at a time needs to use TS, forward a port to a XP machine's 3389. So they logon to that machine instead.