Toastmasters has been mentioned here before, but wanted to post again for people that may have never heard about it. It's a big non profit international organization, that has thousands of clubs all over the world. It's pretty cheap to join. It's not perfect, I think TM is too formal, and it seems at times to produce the same type of speaker. Nonetheless, it does provide anyone who desires the opportunity to get a lot of practice and experience up there on stage and speaking in front of a group of people. It also has a dedicated leadership track which I think is underrated. It's efficient like that.
Go to http://www.Toastmasters.org and find a club in your city. Clubs generally have about 15-20 people in attendance.