Microsoft unveiled Search Server Express 2010. This is a free download from Microsoft and is supposed to be a Google Mini Appliance killer. It’s main drawback compared to the full SharePoint Server 2010 Search is that it can only be used in a one server farm. But still with proper hardware it should be able to index and search about 3 million items with a sub-second response time.
See the compare chart:
As the Search Server is based on SharePoint technology (so effectively comes on top of SharePoint Foundation) it appears the ideal solution for small deployments on premise compared to Foundation itself as that offers only very limited search capabilities: No cross site search, no refinements, no external source indexing.
http://www.microsoft.com/enterprisesearch/searchserverexpress/en/us/default.aspx