Check out the following associations

ABC (Association of Bridal Consultants)
AFWPI (Association for Wedding Professional International)
WBW (Weddings Beautiful Worldwide)
JWI (June Weddings, Inc)

These associations are the best there is, and each have certification courses you should study.

The best person to learn from is Doris Nixon. She is the retired President of Weddings Beautiful Worldwide, and is world famous for her expertise. The person who replaced her is no where near as capable or credible, but the course to become a Certified Wedding Specialist was written by Doris Nixon so at least you would be learning the correct way to be a professional wedding planner. I have heard that Mrs. Nixon is in the process of writing another certification course, but I do not have any specific information as yet.

I am a Certifed Wedding Specialist who had the honor and privilege to have been mentored by Doris Nixon herself, and am in constant awe of her knowledge and experiences.

Just one thing…DO NOT go into this for the money. Do it for the love of the events. Although you do get the expensive weddings now and then, the majority of the weddings are within the average budget. You have to do quite a few of those before you can be recognized among the social elite and land a "big one" (unless of coourse you already have friends in high places).

I have been doing this since 1992 and I have had a radio talk show, have had my weddings make the front page of many major Times newspapers, have written several books and have produced very affluent weddings. It never gets old, (even with bridezillas) and I can honestly say that I still feel like a small fish in the sea. I love weddings, quiceaneras, debutante balls and sweet sixteens. My daughters have also developed the same passion and we work the events as a family. However, we have all given up luxuries and freedoms such as vacations, weekends, holidays, etc. We are always at the beck and call of our brides and each week a new bride is the "Queen" with a never ending barrage of issues.

This is also not a business to enter with little cash flow. Advertising is your biggest cash outlay, and without it, you will not get your clients. At a minimum you will need a DBA name, a dedicated business telephone line with yellow page advertising, business cards, state, county & city licenses, a company checkbook, a website, e-mail, membership in your local chamber of commerce, the local better business bureau, the local rotary club, and the local Lions club or Kiwanis club, and if you county requires it, a resale license. You will need to get involved in local bridal expos and these cost big bucks, not only for the registration fees, but for your booth decorations, giveaways, flyers etc.

Many people disagree with me about the memberships, but here are my reasons for believing they are critical. 1) the BBB provides legal assistance and contract review. So you can save thousand of dollars on legal fees just by joining. 2) All the other memberships require you to network, and for the small fees each club charges, the networks you are exposed to provide you with automatic business that you might not otherwise get. So, even if I only get one wedding from all the clubs per year, the return on my investment would be well worth it.

Besides studying the courses listed above, you may want to volunteer at local businesses to intern with them on some of their weddings. I interned at a florist for 6 months, my church for 1 year, and a photographer for 6 months. These were all during my first year in business. Also, I was a partner in a limousine company. I learned valuable insights as to what is expected, what can and can't be done and how to get what the bride wants within her budget.

I hope you find your way to realizing your dream, but be sure you dedicate the time and money necessary to get the company setup properly and adveretised heavily, because halfass doesn't cut it in this business!

Good luck!
References :
http://www.bridalassn.com
http://www.afwpi.com
http://www.weddingsbeautiful.com
http://www.junewedding.com