Today is the last day to register to vote or change party affiliation for those who wish to cast a ballot in the August 24, 2010, primary election. Even as you read this and you are going to register as a Democrat, that's fine. Voting is one of the most important things you can do as a citizen.
According to the laws in Florida, you must register 29 days before an election, primary or general. On the voter application, it tells you how you can register:
If this is a new registration application in Florida, the date the completed application is postmarked or hand delivered to a driver’s license office, a voter registration agency, an armed forces recruitment office, the Division of Elections, or the office of any supervisor of elections in the state will be your registration date.
So even if you mail it off today, you are good to go. I would just head to your post office and make sure they post-mark it.
Again, you need to go out there and just do it. If you don't at least vote, then you can't complain later After you get register and then you need get educated, and then most importantly, vote. Voting in the primary is just as important.