SharePoint Foundation is the underlying technology for all SharePoint sites. It was called Windows SharePoint Services in previous versions. You can use SharePoint Foundation to quickly create many types of sites where you can collaborate on Web pages, documents, lists, calendars, and data.

Please see the following Microsoft page for information on this topic:

http://office.microsoft.com/en-us/sharepoint-foundation-help/basic-tasks-in-sharepoint-foundation-2010-HA101838891.aspx?CTT=5&origin=HA010370686