Swimming 101

Greetings group I hope this doesn't come across as 'needing therapy' but I need your collective advice. I've recently rediscovered healthy living. I've lost over 50 pounds since March when I began walking, then running while eating better and cutting back on the booze. Yes, I still cuss and spit. The problem began when I upped my running mileage and did speed work. This brought back many of the old injuries which ended my healthful living in my early twenties. I now feel that running will always be a seconday sport for me. I'm simply too banged up and undisciplined to stretch/PT so as to maintain running health. I've choosn swimming as my main outlet. Realize that I hate swimming and have yet to hit the pool. My questions are: how do I learn good form? What is a good beginner's workout? Do I really need to wear a speedo? Do I need to stretch? Will I bulk up from muscle gain? Or can I expect to get that sleek build typical of swimmers? What other advice do you have for a beginner?