Ok, so Charlie (Anthe - Release Manager for the next version of SBS) isn't a horse, but you get the idea . . . . SBS SP1 will include: Windows 2003 SP1 Exchange 2003 SP1 MSDE SP4 SQL Server SP4 (Premium) ISA 2004 (Premium) Windows Sharepoint Services SP1 And on the desktop side: Windows XP SP2 ActiveSync...
The ISA server team has posted a guide on the subject (in three parts). The guide covers most aspects of the subject including troubleshooting. Part 1 Part 2 Part 3