One of the other problems is that the US Census changed from TIGER-line to ECRI format. The latter format has opensource libraries to decode it, but any conversion programs now need to be rewritten from scratch (or at least the translation into the local displayer format). My own zmapper (originally for the Zaurus, but portable QT3 based) stalled for this reason. Meanwhile, Google Maps, Yahoo Maps, MSN Maps... end up working for most things.