Home Location Registry (HLR) and VLR databases

Dear all,

I am interested in learning more about HLR/VLR database systems for wireless
roaming services. Do you know any free implementation under PostgreSQL?

The idea would be to offer a free HLR/VLR service in the European Union to
all 802.11a user. Any information about interactive maps is also welcome.

Best regards,
Jean-Michel POURE