Microsoft have tipped their hand for upcoming integration between Xbox LIVE and Windows Mobile, after a job listing was spotted for a "principal program manager" responsible for "bringing Xbox LIVE enabled games to Windows Mobile". While there are no specifics - and it seems unlikely, given the state of current smartphone performance, that we'll see Xbox 360 titles ported to Microsoft's smartphones any time soon - the initial push appears to be bringing avatars, IM chatting and profile browsing to mobile devices.
"At Xbox LIVE, we're accelerating the trend towards connected, social interactive entertainment by designing incredibly rich, multi-platform game and community experiences. We're connecting players via the LIVE services on new devices beyond the console. We need a Principle Program Manager who can help drive the platform and bring Xbox LIVE enabled games to Windows Mobile. This person will focus specifically on what makes gaming experiences "LIVE Enabled" through aspects such as avatar integration, social interactions, and multi-screen experiences." Microsoft job advert
Beyond that, it looks likely that Microsoft would leverage their Xbox LIVE brand to bring mini-games to Windows Phones, gamers' performance at which would then be linked into their Xbox LIVE accounts. There's no timescale for the rollout of service, however.