I like GPSDash (
http://gpsdash.com) which will give an altitude and horizontal speed histogram and allows you to scan in any graphics file and map an overlay (in a moving-map fashion; you can just use Google Earth for as the basis for a map - it doesn't come with any maps preintalled), and also save your trip for analysis / replay later.
There are about 5 other programs that do very similar things, but this works for me.
Be warned that altitude measurements may not be all that accurate; this is a limitation of GPS technology, and not any software.