Building your social skills is not something you can learn from a book. But if it makes you feel better, I can recommend you the only two books you'll ever need on social interaction:
How to Win Friends and Influence People by Dale Carnegie
How to Talk to Anyone by Leil Lowndes
Those two books have very specific advice on things you can do to be more sociable.
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That being said, the only way you are going to make new friends or meet new people is if you increase your social activities. Someone up thread suggested meetup.com, and I agree that that is a great way to meet people.
Another option is to volunteer for things in your community. (
VolunteerMatch - Where Volunteering Begins)
You don't have to be a club rat to meet people. But you DO have to get involved.