Windows Server Update Services (WSUS) data on Microsoft Small Business 2008 by default is placed in C:\WSUS\WsusContent
This folder can get very large over time, however on SBS2008 you can easily move downloaded data to another drive.

Open Windows SBS Console > Backup and Server Storage > Server Storage
In Tasks Panel click on Move Windows Update Repository Data
Select hard drive you want to move data to and click Move.

This doesn’t move actual database (normally located in C:\WSUS\SUSDB), just the downloaded content. However it should be fine as normally database will occupy less space on the hard drive that actual content.

Windows Small Business Server 2008