Really interesting product launch from Google today! They've announced the resurrection of JotSpot (a company they bought some time back) in a new form as Google Sites.
Google Sites allows easy creation of collaboration based websites with wiki and team-site features. It's tightly integrated into Google Apps allowing you to integrate spreadsheets, docs, calendars and other features into sites with uses such as intranets, extranet team sites and company portals.
Looks very cool and is a real alternative to Microsoft Sharepoint in my opinion. The video below gives a really good overview.
More details here on Google's blog