There is the Game Developpers Conference 2004 in San José. Gamsutra did a webpage about this event (live news coverage). I wish I could attend Amy Jo Kim's talk about Social Trends in Mobile Entertainment.

To create great mobile games for this audience, we need to understand how they use cellphones, and what role 'mobile relationships' play in their lives. In this short talk, online community expert Amy Jo Kim provides attendees an overview of the most recent ethnographic research into mobile useage patterns and emergent social phenomena, and demonstrate how fast-growing mobile services like UPOC and ImaHima are riding this wave by helping phone users maintain and grow their social networks. This session concludes with a summary of the key social trends that are important for mobile game developers to pay attention to.