I recently downloaded the Visual Studio 2010 Beta 1 and have been playing around with the different features for Office Business Application development. For the public Beta 1, you’ll be limited to the 2007-centric templates (e.g. Excel 2007 Add-in, Word 2007 Document, etc.), but the nice thing is that if you’re familiar with these templates when future Betas are released you’ll already have had a chance to get experience with the Beta 1
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Another Office Customization with Beta 1 – Excel Add-in with Custom Task Pane