People on here run at all sorts of different weights. I attempted C25K like maybe 5 times but the time it stuck and I completed it, I started out in the 240s (I was in the 220s by the time I was done).
C25K (Couch 2 5k) is a beginner running programme (8 weeks if i remember correctly). If you're considering re-starting running, I highly recommend you take a look at it/ try it out to see if it's something you're ready for or you want to do. Even if you're not ready to do it now, it's something to work towards. When I finished it, I wasn't running 5km but I was running 30 minutes straight. And even though it's been over a year since I finished, I've kept it up and still "run" pretty regularly. I'm wayyyyy faster than I was but I also wouldn't call myself a "runner." You can find more info about C25K here:
http://www.coolrunning.com/engine/2/2_3/181.shtml and also check the exercise board. I think they have a support group there. Actually most of the boards on here have a C25K support group just do a search if you can't find them.