There are a couple of things specific to RA that are added in SBS.
Besides just reading XP help, you should also read SBS documentation as they
made it integrated into the server management console.
In a nutshell - connect to the server via RWW, open Server Management, click
on Users in the left pane, click on offer remote assistance in the right
pane. Type in the machine name or IP, and you are done.
A demo is worth a thousand words, so here you go:
Leonid S. Knyshov, CEO
Crashproof Solutions, LLC - http://www.yqcomputer.com/
MCP Exchange 2003/Small Business Server 2003, CCNA, SCSA 8, NCIE
Microsoft Small Business Specialist Partner