i dont think you can use telenav on an at&t branded phone. you can only load the at&t navigator (which i think is the same thing, just more expensive and at&t branded).
Sprint offers free tele nav just a gps. Then the upgrade to plus is 4.99 a month and gives you speed limits and ect. AT&T nav gives you the same for 10 bucks to say only big red offers this is foolish.