We’ve been providing means to migrate your data from VSO to an in-premise TFS, but not the other way around.  Until now!

We just announced a new integration service from OpsHub that allows you to migrate your data from your on-premise Team Foundation Server implementation to Visual Studio online.  Full details can be found here, in the Visual Studio Gallery.

From http://visualstudiogallery.msdn.microsoft.com/28a90a17-d00c-4660-b7ae-42d58315ccf2

While you’re at it, take a look at the other capabilities that OpsHub offers.  They have an amazing line-up of ALM systems that they can integrate with their Integration Manager solution.