When Microsoft unveiled the critically-hailed Windows Phone 7 Series operating system at the Mobile World Congress show in Barcelona last month, it promised more details on applications and developer programs would come this month at the MIX developer conference.

Now, a few useful details are beginning to emerge. For starters, there’s a full lineup of apps already ready to go for whenever phones with the new software goes on sale, expected later this year. On the music end, they include customized Internet radio service Pandora, and music ID app Shazam.

To set itself apart from the iPhone, Microsoft is allowing users to demo these and other apps in the Marketplace before buying any of them. That Marketplace also supports one-off credit card purchases as well as carrier billing integration and ad-supported free apps.

The developer specs unveiled at the event allows for deep linking, which means apps can cross-promote their applications by merging functionality. There will also be multitasking—allowing apps to run in the background while using the device for other purposes—as well as access to location data, push notifications and integration with Window’s Silverlight video software.

A good roundup of all the features and capabilities of the new Windows mobile software is available at Gizmodo .