Totally agree with Nanley. The hardest thing about learning to run is not the fitness, but the time it takes for your leg muscles and tendons to adapt to the impact. Building up a solid walking base, then a Couch to 5K plan is definitely the way to go.
First, you'll want to build up a solid walking base. When you can walk 5k, that's a good point to start working on running. You'll also need a good pair of shoes, fitted at a running store.
Then, you can use a Couch to 5k program, which will start you out by alternating intervals of walking and running. The walking intervals gradually decrease and the running intervals gradually increase until you're running the whole thing. I did this particular program:
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