In September 2009 it was reported, (for example on ReadWriteWeb and Silicon Florist) that the city of Portland has a proposed resolution to make the city's data open. In particular the resolution says:
WHEREAS, by sharing data freely, the City of Portland seeks to develop opportunities for economic development, commerce, increased investment, and civic engagement for Citizens of the Portland region; and
WHEREAS, publishing structured standardized data in machine readable formats creates new opportunities for information from different sources to be combined and visualized in new and unexpected ways, for niche markets to be identified and developed, and for Citizens to browse, interpret and draw attention to trends or issues with greater efficiency;
At time of writing there does not appear to be an official registry of published data.