Location based services are currently being held back by network operator inactivity. With the exception of a few operators there’s no developer access to location information. This information, does in fact exist for the majority of network operators because in many countries it’s usually a legal requirement to provide it to security services as part of the granting of a GSM/3G license. It’s just that operators can’t share the information due to privacy concerns and the lack of perceived business case (revenue model).
There seems to be a resurgence of ideas for location based applications at the moment, mainly as part of user-centred design and context aware services. So, how can these be implemented? One approach is to talk to network operator. However, unless you can provide an immediate revenue stream for them I don’t think you will get them to listen. Another approach is to use cell id information and map this to geographical location. This isn’t as difficult as it sounds. MobiLife provide free Python (Series 60) based applications to get you started. There’s even the start of a database at GSM cells and Cell Spotting.