I would start slow at a slow pace, with intervals and shorter distances to start with.
Lets say 3 times a week, and then add on some more when it feels "easy".
There are several great apps which can help and give you motivation! I use Runastic, which is free and very useful.
Best of luck!
Anna
Nobody in the medical profession except a fellow runner will advise you to run -- it's really hard on the joints. But running is really fun and I really miss it now that I can't do it, so if you want to do that and your body is healthy, go for it -- life is short, do what you love. Cholesterol isn't necessarily a sign of anything -- the connection between cholesterol and heart disease is there, but there's no consensus for how important it is in and of itself. You can also have healthy high cholesterol if your HDL is high and your LDL is low. It will be high but because the good part is high. But again, if high cholesterol is your only problem, we don't even know if it is a problem, but as the above person noted, start off running slowly and for a short distance. Work your way up with any new form of exercise so you don't get hurt and end up on the bench again.
You know, if you are motivated to run and have run in the past, I don't think a 3-year gap will make it dangerous to run again. You will take your cues from your body and won't overdo it, I'm sure. Then see the doc and get your checkup.