Each track point from maemo-mapper look like this
<trkpt lat="45.810874" lon="-74.128640">
<ele>240.00</ele>
<time>2008-01-27T16:36:01</time>
</trkpt>

It would be nice to have the speed data so to plot the speed data during a track.

I have found this site that does just that:
http://www.gpsvisualizer.com