Apologies if this is a repeat, I didn't read through every prior post, figured I'd add this, as it was the answer I got when I was trying to find an official nav download:
Nextel/Sprint - Windows Mobile Devices
Installation Instructions
- Tap Start
- Tap Internet Explorer
- Enter http://ota.telenav.com/ota/sn/ in the address bar
- Tap the green arrow or Go
- Checkmark "Open File After Download"
- Tap Yes and wait for the download to complete
- Tap OK to install - this will take less than a minute
- Tap OK or X in the upper-right corner to return to the main screen
- To launch TeleNav Navigator, tap Start, tap Programs, tap the TeleNav icon