For beginning runners, I must recommend Katharine Switzer's Running and Walking for Women Over 40. We used her ten week plan to get up to 30 minutes a day. It definitely took us longer than ten weeks, but it did work. I used her second ten week plan to get up to 60 minutes a day. It took about twelve weeks, I think. In the interest of preserving my ACL, I'm dropping back to 30 minute runs. In a week or two, I'm going to start the slow and methodical process of working back up to 60 minutes.
I will never be a fast runner. I can be faster than I am now, but never just *fast*. I am unfortunately all slow twitch muscle. This would be good if I had the long, lean body of a marathon runner, but no, I'm stocky and close to the ground. I bulk up easily (with both fat and muscle) and should have been a sprinter by rights. Too bad about the reality of genetics.