I played around with a bunch of settings after the holidays and was never able to pair data services with my TomTom.
To my knowledge, AT&T is the only US carrier currently with a network that supports data and voice transmission at the same time; so, even if I did, I'd have to pick between using the TomTom's data services or being able to make or receive phone calls.
In all honesty, neither is a concern for me, as I rarely make or take calls while driving and have opted for the less expensive RDS-TMC antenna for my traffic updates; however, I'm sure there are a lot of people who want Traffic Plus, and call capabilities at the same time.
So I don't have to lug my TomTom around everywhere I go, I'm trying
Garmin Mobile on my BlackBerry and have been pleased with the results. Although, I don't like having to enter a complete address, I do like that the Garmin application actually tells me what side of the street my destination is on.
The major Pro to Garmin Mobile is that it only costs $99 USD to navigate in the US and Canada for the life of the phone ($120 USD to navigate Europe); less than the cost of a year's worth of map updates and a traffic subscription on the TomTom.
Although this price is not transferable to a new phone, I usually keep my phones for at least four to five years, so, $99 USD is not a bad price to pay, considering it includes a constantly updated map, free traffic, free weather and more.
The major Con to Garmin Mobile (at least for the BlackBerry) is that it won't let you store maps on an SD Card, so if you lose your data or GPS signals, you lose your turn-by-turn directions.
So for now, I plan to use Garmin Mobile in urban areas where I won't lose my data signal (and spend 99% of my time) and use my TomTom if I ever travel into a rural area; where I'm lucky if I can get a voice signal, let alone a data signal using T-Mobile's GSM network.
I highly recommend anyone with a BlackBerry download the free trail and see for themselves.
Even better, if anyone is willing to also buy soon,
Handango is offering Garmin Mobile (and a bunch of other applications) for 25% off through the end of this month.
I do recommend downloading the trial first and making sure your phone can acquire Garmin's satellite signals. It took my phone 10 minutes to acquire a signal the first time, but I haven't had troubles with it since.
I'll post a better review of Garmin Mobile versus TomTom, after I've used it more; I especially want to see what Garmin Mobile does (or does not) do when driving through downtown Minneapolis, as to my understanding, tall buildings are notorious for blocking GPS signals.