For years Teamprise have provided integration between Eclipse and Team Foundation Server. Teamprise also works on mainframes.

The collaboration continues: At the European Eclipse conference Microsoft announced improved support for Eclipse and the Windows world. In short Eclipse will get better interop support for Windows 7, Windows Azure, Silverlight and others like ADO.NET Data Services.

“Microsoft teams with Tasktop Technologies and Soyatec on open source projects designed to foster interoperability and make Eclipse a first-class tool on the Microsoft platform.”

Source: Partnering to foster Eclipse and Microsoft platform interoperability

Press release: http://www.microsoft.com/presspass/press/2009/oct09/10-28eclipsepr.mspx