I'm no pro, but I have managed to lose and keep off 60lbs. 🙂 Though, I am 6' flat and 174lbs now.
First thing, start managing your diet. Cut the excessive calories = less fat intake. I eat about half or a quarter of what I use to. Instead of making two sandwiches or whatever, just make one and wait about a half hour. If you're still hungry, make another or have something else to tide you over. Cut out the soda completely as that is just empty calories and caffiene.
The weight you should start at is whatever you are comfortable with. If you have to start at 8lbs or something, then that is that. Don't over-do it or you could damage your muscle tissue. Start low, then work up. Keep a log of how many reps/sets you do and the weight you are doing so that you can keep track of your success. Don't get envious if the guy next to you is doing 4x your body weight...chances are he's been there for a while and has gained the proper form and strength. Speaking of form, keep a good balance when you lift. If you are swaying this way and that, you aren't doing your body any good. Keep still as you can and lift the weights up and down in an equally paced motion. Don't go up or down too fast as that could cause unnecessary strain.
I'd say start out 3 times a week. Say, MWF or something. I believe the current 'doctor's recommendations' is 5 days a week with 30 minutes of cardiovascular exercise to keep your proper weight. Of course, that is with a balanced diet.
Always eat 3 meals a day, or more, as it depends on your body. I personally eat ~5 smaller meals a day, which helps keep your metabolism quick, your stomach not so full, and puts less strain on your digestive tracks.
Treat yourself to a sweet candy or something maybe once every 7-10 days so that you don't get that, "Oh, I can't eat that anymore at all!".
Well, that's a start! Good luck!