I have tried TomTom Mobile 5 and TomTom 6 Navigator on the T-Mobile Dash. I prefer TT5 simply because it's design for SP unlike TT6 Navigator which is design for PPC. If you want to use TT6, you have to download a program called "Fakecursor" (mouse emulator) or something similar called "SPHelper" to emulate a touch screen arrow because TT6 is touch screen capable only which is pretty annoying. You basically use your arrow keys to move the mouse and the OK button to confirm the spot touched on the screen. The TT6 has a more updated map + better GUI compare to the dull but pretty good TT5. Both softwares work with other Bluetooth GPS devices. I currently own the Holux GR240 which is SirF III; something you would want to look into when purchasing a gps receiver. One downside I don't like when I use TT5 is you have your nice qwerty keyboard, in this case the Dash, but the program uses the old way of inputing the alphabet/letter/symbol you want and you CAN'T CHANGE it. In other words, in order for you to input E in TT5, you have to click on the 3/R button twice despite the fact you already have an E button left to it. Any other keys beside the number keys are fine to input like T,Y,U,I,O,P etc.
