I can tell you that doing Kegel exercises DO WORK! You have to work at it for at least a month every day to see some results. I am the same way as you, uncircumcised and it's so sensitive it feels so good that I could cum within a minute if I let it happen.
Google around and find the PDF called "How to Make Love All Night (and Drive a Woman Wild).pdf" This is what I read when I was having my premature ejaculation problem. It's easy reading, and basically it tells you to do your exercises and be aware of your different levels of sensitivity and excitement during sex. When you feel yourself getting close you are to flex and hold your PC muscle and stop thrusting. Go back down a level and continue on. When I was single I couldn't believe it when it worked for me, I had a new girl and I was able to keep going! Sex is very mental too, if you want to last you can't always be thinking of what's going on around your wang, that will over excite you. So you have to think about other stuff or whatever. Just read it! it WILL WORK!!!