I just found the proceedings of Mobile Entertainments: User-Centered Perspective, a conference which happened in 2004 in Manchester. I already blogged about some paper about it but now it seems that the whole proceedings are online which is good. Some papers are business oriented (consumers' insights...), other are more HCI-related with a strong focus on users understandings and sociology of mobile gaming.Here are the ones abotu location-based games:

On the Streets with Blast Theory and the MRL: ‘Can You See Me Now?’ and ‘Uncle Roy – All Around You’ by Duncan Rowland, Martin Flintham, Steve Benford, Nick Tandavanitj, Adam Drozd & Rob Anastasi page 115

‘Gangs of Bremen’: The First Prototype of a Mobile Game by Jochen Hahn & Katja Fahrenholz page 125

On the Development of a Mobile Play Mechanic by Barbara Grüter & Anna Mielke page 133

The Design History of a Geolocalized Mobile Game: From the Engineering of Displacements to the Engineering of Encounters - A case study of the development of a mobile game based on the geolocation of terminals by Christian Licoppe & Guillot Romain page 149