Check it out here: http://sharepoint.microsoft.com/2010/Sneak_Peek/Pages/default.aspx

Microsoft has posted three great videos detailing improvements for three roles of users including a general overview, IT professionals and developers.

Some of the highlights include:

• Ribbon support (with live preview and context aware)
• Visio Services
• BDC revamped to the Business Connectivity Services
• Groove revamped to SharePoint Workspace
• SharePoint Web Part
• Large List Management (Means potential support for > 2000 item limits)
• Better disaster recovery options
• Visual Web Part development
• LINQ for SharePoint
• and a really interesting Developer Dashboard that provides important statics about code running within a SharePoint page