One thing that's helped me out a lot is pretty much along the lines of what Wattage said, although, I didn't have the privilege of walking, so what I would do is jog, really, really slowly! lol
But I would go for time, rather than distance, because you know my cousin (who used to accompany me on my runs) can run 2 miles in 11.5 mins! I can't do that!
So it helped me out to run for a certain amount of time....no matter how slow, then once I got used to running a certain amount of time, I started trying to speed up. Not too much, but a faster pace than my previous one....I would measure my distance and see how far I would go in 45 mins. or so.....then the next week, I would try to beat that distance in the same amount of time, and so on and so forth.
But definitely start walking for time, and measure how far you go, pretty soon you'll be running like 6 miles in under an hour! well maybe not, but you know! and listen to giz2000, the wrong shoe could give you unecessary injuries, and my own bit of advice, hydrate and stretch! stretch before and after each workout!
