YES! Running is GREAT! I'm at 223, and I'm training for a marathon! And trust me, if I can run, then pretty much anyone can... A few tips:
1) Make sure you have good shoes. Many running related injuries (to knees, hips, ankles, etc) come from running in old or inappropriate shoes. There are stores available to do a gait analysis (don't worry, you can actually
walk for this, rather than run, if you need to), and the salespeople there are usually very informed and can help you choose a shoe that provide the support that the rest of your body requires.
2) Start small. The first day I began running, I couldn't even run 100 yards! But slowly, I began to notice that I could run farther and farther. Eventually, I was running several miles without ever needing a walk break. Lots of times it seems like people give running a try, but then they quit because they are frustrated and think that they "can't do it". In reality, you just have to have realistic expectations of yourself. Start out trying the walk/run technique (Walk 2 minutes, then run 1, then repeat). Then adjust as necessary. The key is to allow yourself time to recover, and you'll be able to cover a lot more miles. I have some great book recommendations for runners, if you're interested.
3) Start small. Many injuries come from starting out too quickly. Allow your body the time it needs to get used to this idea of "running". If you go out on your first day and try to run 5 miles, I'd be willing to bet you won't try running again because A) it'll be the worst 5 miles of your life, and B) you'll be so sore you can't move. Of course, this varies person to person, but for most people, when running is new, it takes a little while to work into it. Just do it a little bit at a time.
4) If you're like me, you'll need a really good sports bra. Because running is a "high impact" sport, there's a lot of bouncing in the chest-al section that go along with it. I have been lucky and have found a couple of sports bras that work well at Dick's Sporting Goods. They're made by Champion. I just try to find the most supportive ones that I can. One of these days, though, I plan to buy one by CRX. They are fantastic, and I would love to have one, but I can't seem to fit into their largest size yet. Oh well, give me another 6 months and I'll be there.
5) Don't worry about speed. My "run" is slower than some people walk. It's more of a shuffle, really. But it works for me. And I've noticed that I've gotten faster over the months without really even trying. So, just get out there and move, at whatever speed you like.
6) Finally, try not to worry about how everyone else on the trail looks. When I first began, I felt painfully aware that i was the fattest person out there running. But running folks are usually very friendly. Never once has anyone made fun of me or laughed at me for trying. In fact, it's been just the opposite. Because I'm heavy, people seem more supportive. Many times, I've had complete strangers shout to me on the trail "Keep it up!" or "You're doing great!" Complete strangers! It's actually a very supportive network of people; runners are intimidating, but once you're out there with them, you become one of them.
That's pretty much it! Good luck to you! Running is really great. After a great run (even a short one) I always feel strong and liberated and healthy... You can do it! Check out my weblog, as well... It's mostly about running, with a few little humorous tales of my life thrown in for seasoning:
slowgirlrunning.blogspot.com