I have a data plan so I don't know if telenav will work without it, I would guess that it wouldn't though. I bet there is other software that doesn't need a dataplan though, just a GPS reciever.

I like telenav a lot, its got a ton of features (including audible turn by turn and automatic recalculation of directions if you go off course) it's $9/month though which is a downside.

Edit: I use Telenav, not intelinav sorry for the confusion!