"Small Business Server (SBS) is designed to be the only software sitting at the centre of a small-business network. The wealth of functionality includes Windows Server 2008, Exchange Server 2007, Office Live Small Business 2008, Windows SharePoint Services, and Windows Server Update Services. Network and server security are available with SBS, though they're not included in the basic price. You'll get a trial licence for ForeFront and Windows Live OneCare, which extend malware coverage to Exchange and all Windows clients on the network. If you want to continue to use them, though, you'll have to pay for additional on-going licences.
With the release of Small Business Server 2008, Microsoft shows signs of understanding that small businesses have a wider range of server options than ever before. For most small companies, SBS 2008 will provide the basic functions necessary for the business in a package that is easy to set up and administer, and that integrates readily with Microsoft Windows Vista and XP clients. The purchase price won't be as low as Linux, but the polish and ease of use are both high, and the single-user CAL makes SBS 2008 the most affordable SBS yet. Microsoft has been listening - and this time, it shows."