Microsoft announced along with the Windows Mobile 6.0 platform new Windows Live features for mobile phones and a media platform for mobile devices called PlayReady at the 3GSM 2007 in Barcelona.

Live Search for Windows Mobile and Live Search for Java provide customers with advanced local search and mapping capabilities on their mobile device. In conjunction with the availability of Windows Mobile 6, Microsoft also introduced Windows Live for Windows Mobile to search emails, IMs and files on your Windows Smartphone.
The Microsoft PlayReady new multimedia content access technology optimized to meet the needs of mobile operators and handset manufacturers.
Content types supported by PlayReady include music, video, games, ring tones and images. Audio/video formats supported include Windows Media® Audio (WMA), AAC/AAC+/HE-AAC, Windows Media Video (WMV), and H.264.

Telefónica, O2, Verizon Wireless, Bouygues Telecom, and Cingular Wireless, now the new AT&T indicated plans to deploy (meaning Microsoft could not lock them in yet) PlayReady.

More details about the Windows Live for Mobile can be found in this Microsoft press-release and on this Windows Mobile Live site.
Details about Microsoft PlayReady are to be found here.