The Windows Essential Server Solutions products, specifically designed for for small and midsize businesses shipped this week. The servers included Essential Business Server (EBS) 2008, Microsoft's first-ever bundle for midsized businesses and Windows Small Business Server (SBS) 2008.
The two bundles help serve the needs of businesses that have up to 300 PCs.
Windows Essential Servers combine Windows Server 2008, Exchange 2007, Windows SharePoint Services, Microsoft Forefront, Windows Live OneCare, and more. Some versions include SQL Server 2008. You can compare version at Editions Overview. You can try out Windows Essential Servers at Try It.