http://www.endomondo.com). Endomondo uses the internal GPS of the BlackBerry to keep tabs on your route and hence distance travelled. Once it knows the type of exercise you do and the distance it can calculate the amount of calories burned, it is by no means hugely accurate, but it does help. It also tracks on a whole lot of stuff like total calories burned, fastest mile, 3 miles, 5 miles, etc, total distance travelled, etc. They also have monthly competitions to track total calories burned, or distance cycled or whatever, for that month. Its not that I ever think I might win but it is fun to track, daily, where my position is in the stats, did I go up or down. It really appeals to my geeky side, but more importantly it motivates me to keep on going and helps me keep track of how my friends, even those very far away, are doing, and vice versa. Endomondo will also allow tracking in real time, the person viewing the website can also send 'pep talks', assuming you have headphones plugged in, very handy for stuff like, 'you're doing well', 'did you fall asleep' or 'can you grab some milk on your way home'. It is all good fun and adds just a wee bit of motivation. Sometimes the GPS in the BlackBerry can be very inaccurate, moreso when the device is doing other stuff, it doesn' happen often, but when it does it can lead to interesting results, see here - http://www.endomondo.com/workouts/u0_kAkQNOuI, just for the record, I did not decide to go for a stroll across Southfield freeway one lunchtime, or run around like a crazed idiot.
https://buy.garmin.com/shop/shop.do?pID=11039#owners. I ended up buying a rather fetching green refurbished unit on eBay, although it does come with a 1 year warranty from Garmin, so that was good enough for me. It has a number of nice features, built in GPS, etc. The watch does way more than I use it for, but I will grow into it over time. One feature I have started using is Virtual Partner. Basically you put in the pace you want and it will show you how you are doing with respect to that pace, ie amount ahead and behind in time & distance. It is kinda cool when you are shooting for a particular time.
If there is one thing that sometimes can be a pain is staellite acquisition time, ie the time it takes get a good position, there is a nice screen that shows satellite status and GPS accuracy, if it isn't homing in, I can switch off & on the GPS and it gets better. When going out running I tend to switch on the GPS when I leave the house and by the time I get to where I start running it is all ready to rock and roll. Garmin is a GPS company so I'll trust them, it does seem more accurate than the BlackBerry.
Here is my profile on Endomondo - http://www.endomondo.com/profile/360526