The safest route is to install TT6 in your root folder on your Storage card, i.e.
Storage Card\2577
Storage Card\Guam
Storage Card\Voices
etc
the start, ttnavigator files, etc are in the root portion of the storage card too
Its not clean but it works -- I have had MIO, Tom Tom and Garmin all installed at the same time -- but I prefer Garmin XT because it has the new 2008 maps. Hopefully the IGO8 North Amer maps will come out soon, so I can test that one too
I am constantly testing the GPS software -- but I never go anywhere.
Mule