I would also recommend a "Couch to 5K" running plan.
Cool Running :: The Couch-to-5K Running Plan
Oh, and don't forget to get yourself a decent high impact sports bra!
I have only managed to download the podcasts without progressing to actually following the programme. Oh well, I am half way there!!!
Don't mean to go off tangent on the thread but saw this and am just wondering where is best to get decent sports bra's in larger sizes?
In order to do some running, make sure that you invest in a really good pair of trainers, rather than a cheap make, that will "do". Also, I would recommend a couch to 5k running programme - you can find loads of them if you do a search in google or yahoo and there is loads of advice that comes with them.
Take things easy, never expect to run a marathon the first time you set out...and remember to warm up and cool down.
Good luck!!
x