"Best man"

I was at work earlier, and my best friend stopped by to see me. He was with his 'girlfriend', or so I thought. Then he told his girlfriend to show me her 'engagement ring', at this point, I was shocked. I said "Grats, my white brother from another motha!" and hugged him and his now-a-fiance. So then he surprised me by saying that I will be his best-man at the wedding. The wedding will take place in about a year. I think I'm supposed to make a toast, right? Anybody have any tips that have been a best-man at a wedding? Or anybody that has done any toasts? Thanks. Like, I really need help. I want to make a really awesome toast for my bestfriend.