Microsoft is hosting a Windows Phone developer summit on June 20-21, and recently sent out press invitations for a June 22 event in San Francisco that promises “a sneak peek of the future of Windows Phone.”

While the invitation doesn’t specifically mention Window Phone 8, insiders are saying the event will unveil new developer services for creating apps for the new Windows 8-based kernel of Windows Phone 8.

Windows Phone 8 is widely expected to include improved hardware support for multi-core processors, four screen resolutions, and NFC radio support with a contact-less “wallet experience.” Microsoft will likely integrate its Skype app into Windows Phone 8, and offer native code support for developers and app-to-app communication support. Some of these upcoming features are expected to be revealed at the Windows Phone Developer Summit on June 20th.

Handset manufacturers are expected to release the first Windows Phone 8 handsets later this year.