One of the really cool features of Sharepoint has always been its ability to search through all the content on your site. Now Windows Sharepoint Services (ie the free edition) did a great job but not as much as the full blown Microsoft Sharepoint Server (MOSS, ie not free). The MOSS product search had far more functiinality and things like "did you mean", "sounds like" and so on.
Well now Microsoft are making a version of this Enterprise Search available for FREE yes FREE. It's called Search Server 2008 Express and you can find out more info by clicking here.
It looks really good and should be an excellent add on to Windows Sharepoint Services, however on the initial reading we think it may have trouble if installed with Sharepoint 3 on SBS. We will confirm this as we are currently in the process of test the Release Candidate which you can download.
We'll post more information about what we find soon.