The VSeWSS project upgrade tools for Visual Studio 2010 beta is published here. It is planned to be published as sample code for the release of Visual Studio 2010.
This is an additional project template for Visual Studio 2010. When you create a project from this template it will ask for an existing Visual Studio 2008 extensions for Windows SharePoint Services (VSeWSS) project. When you select the previous project it will create a brand new Visual Studio 2010 project that uses the new SharePoint 2010 project templates which are built into Visual Studio 2010.
Please review the README for the tool to get the best use from it. It should upgrade projects created with VSeWSS v1.1, v1.2 and v1.3 March CTP. The project must already have been compiled using the previous version of Visual Studio. You cannot use the VSeWSS project templates with Visual Studio 2010 so this upgrade project template is the best way to migrate your VSeWSS project to Visual Studio 2010 and SharePoint 2010.