Microsoft has opened registration for a Windows Phone Developer Summit set to take place next month in San Francisco. Invitations for the event recently went out highlighted by the tag line “A sneak peek of the future of Windows Phone.”

Redmond announced the Developer Summit about a month ago but little was known about it until now. For starters, Microsoft has shortened the event from a two-day affair to a single-day shindig. It’s unclear why the function was shortened, but that’s discussion for another day.

The aforementioned tagline is likely a hint that Microsoft plans to show off the next-generation of Windows Phone, codenamed Apollo. We already know a great deal about Apollo thanks to a leaked video that hit the web in February.

In that clip, director of the Windows Phone program Joe Belfiore outlined several hardware features in upcoming Apollo handsets including multi-core support, microSD card support, multiple screen resolutions and NFC functionality.

Information on software functionality was even more abundant with claims that the next Windows Phone will use many of the same components as Windows 8, meaning developers can easily port their code to mobile devices and vice versa. We can also expect to see Skype integrated into the OS as well as a new feature known as DataSmart that makes it easier for users to track data usage.

The Windows Developer Summit takes place on June 20 at the Marriot Marquis San Francisco. Those interested in attending the summit can register by clicking here. If you can’t make it to the event, you can hit the Channel 9 site for full coverage.