unfortunately AT&T blocks installation of any apps except from the market place. Hence you need to root the phone to remove that block to install an .apk file that is downloaded from a web site.
I did download the lastest version (0.9.

from the market place and installed it. I see that for tracks from the database it is possilbe to move the map to show the track after selecting it. For tracks from "My Tracks" on google, however, Locus does not seem to move to the track after checking and loading it and the context menu item that says "Map" for the tracks in the database, says "Share" for the track in My Maps.