Yes, Scout333- a FSA allows you to set aside pre-tax money to use towards your medical/dental/vision expenses for the year. You select the dollar amount for the year, and then it is deducted from your check bi-weekly.
When you have a doctor co-pay, or a prescription expense, you simply download the PDF form from the FSA website, fill it out, and then send in the form, along with your insurance company statement of benefit, if applicable. The FSA then reviews your claim to determine if it's eligible, and sends the money to your bank about in about a week. It's fast, easy, and works well.
Like everyone says- the trick is to make sure you set the right amount- because if you set aside too little, you run out soon. And if you set too much, you lose the money the following year.
Here is a link to some videos about FSA's through FSAFEDS:
http://shps.http.internapcdn.net/shps/
The first year they became available, I set aside about 2K for my family. It turned out to be a little more than I needed. So I downsized it the next year to 1K, and that was about right. I came up a few bucks short, but I didn't lose anything. Some people set aside far more, and use it. Others set aside less, but I guess it all depends on what you think you are going to use for pre-tax medical expenses.
FSA's are fairly new to the Federal Government- Congress first approved FSA's for federal employees in October of 2002, and the IRS allowed a 2.5 month "float" in the time period starting in 2006.