Streets & Trips 2006 for Smartphone seems to be working fine. Upon installation, it gave a warning that the software might not work because it was designed for an earlier version, but it appears to be running without problems.

I was able to use the same maps I had created for my 6700 (actually just left them on the 1 Gb card I moved from the 6700 to the Q). When I opened the maps, they were fine.

MS generally releases the next Streets & Trips each year in late summer, so it may be best to wait if you don't already have 2006. The 2006 version included all three versions (PC, Windows Mobile, and Smartphone) for about $29 -- one of the truly great software bargains out there.