What is the best (free) software for viewing osm on symbian (9.4) phones?
Have a look at the omniscient OSM wiki about http://wiki.openstreetmap.org/wiki/Symbian
personal opinions about the best one might differ … so try each on your own and report if you get stuck somewhere or something fails.
GpsMid ( http://gpsmid.sourceforge.net/ ) should work fairly well with Symbian as well. It is a JavaME program, but Symbian has a fairly decent java runtime environment.