There's no info on the V400 supporting GPS, and nothing on the manual about it. The only Moto phones that I know of that support this are the i205, i305, i530, i710, i730, i733, i736 and i830 -- most if not all carried by Nextel or SouthernLINC in the US and Telus in Kanada.
Accutracking (http://accutracking.com/) offers software that lets you use the phone as a sort-of receiver. Check their website for a list of functions.
As to whether or not you'd want to use this instead of a dedicated receiver is dubious. I don't know anybody that has one of these phones (most people I know hate Nextel ) so I can't comment on the functionality, update frequency, etc. Whether or not the data itself could be ganked and used in some other mapping software is also up in the air... could be easy, could be hard.
There is a ton more info on different GPS phones and carriers here: http://www.gps-practice-and-fun.com/gps-phones.html
Incidentally, I don't think you posted this in enough forums... What is this, the 4th place where you posted the same exact question?