Earlier, I wrote a post on Column Validation and List Validation settings in SharePoint 2010. If you are wondering where to get help for the currently supported formulas for SharePoint 2010 beta 2, then here is the ‘precious’ link for you - http://bit.ly/sp2010-formulas

If you are still stuck with any of the formulas, feel free to discuss it at the SharePoint 2010 MSDN Forums