It is uncertain what the InfoPath development story is for Visual Studio 2010. Christopher Brotsos a Microsoft program manager on the InfoPath 2010 team indicates that there is no Visual Studio 2010 support for InfoPath development.

http://social.msdn.microsoft.com/Forums/en/officedevelopmentprerelease/thread/18a93486-0773-44cb-ae04-cc4b8f75c205?prof=required

So how does one create InfoPath 2010 forms that have code? Say “hello again” to Visual Studio for Applications. Philip Newman and Christopher Brotsos show how to create forms with code by flipping between InfoPath and VSTA. Oh, and if you want source control integration too, then you also get to flip to a third application, Visual Studio 2010, to perform your check-in / check-outs.

http://blogs.msdn.com/b/infopath/archive/2010/06/10/using-tfs-for-source-control-in-infopath-2010.aspx

I can’t help but feel that InfoPath development has taken a huge step backwards with the Visual Studio 2010 / Office 2010 product releases. Here’s hoping that a service pack makes things better.