Microsoft Exchange Server and
Blackberry Enterprise Server news, views and fixes.
At last Microsoft have released the installation tool for Exchange 2007 SP2 on SBS 2008.
Looks fairly straight forward to use, download the service pack as normal, download the tool and then run the tool.
You can get more information about the tool and download it from this KB article: http://support.microsoft.com/?kbid=974271
Exchange 2007 has been rock solid in my experience and if you were put off installing it on your SBS 2008 machine because this tool wasn't released, now is your chance.