Stop with the negative self talk.
"I'm always nevervous. I NEVER know what to say around my friends. I CAN'T DO IT."
Successful people never talk negatives.
You've acknowledged that you may have problems talking to people. That's an awesome start. Focus on the positives.
Rather than telling yourself "I Can't"..focus on doing small things everyday.
Instead of whole conversations with people...try just saying hello to them and smiling. Then build on it. Start with long conversations with family. Then with friends. Then with strangers. Then with women.
Give yourself a deadline. By next week...I plan on saying hi and smiling to everyone I meet. By next month..I plan on having conversations with my family. By next summer...I plan on having open conversations with women.
Good tip - Surround yourself with positive people..funny people..people who make you laugh.
Comedians are so well loved because they know how to communicate with to a crowd. Buy some dvds, rent some dvds. Get into some good stand up comedians, story tellers like Eddie Murphy, Richard Prior, Dave Chapelle, Martin Lawrence...watch these artists at work and imulate their attitude and charm. See how they talk, act, and verbalize and add that to your personality.