I recently took a salaried postion in Central Florida. During my interview I was told that it would be a 40 hour week with OCCASIONAL overtime when busy. Since July, I have been consistantly putting in 20 + hours a week due to the heavy workload that they have given me. It is not only me though, it is the entire group of people who put in these kind of hours without any type of compensation.
The company normally shuts down for a week during Christmas, but because I have not been there for at least 6 months, I may not get paid during this time off. Since I have put in all this extra time, can they actually dock my pay? Is it legal to have workers continually work these hours without any type of compensation, especially when this was NOT disclosed to me during my initial interview? Many of the other workers who have been working there for some time have told me that this is the way its been for years.

If by "salaried" (which is merely a pay method), you mean "exempt", you are never legally entitled to any additional pay over and above your weekly salary, no matter how many hours you work per week and no matter what they may or may not have told you at hire. The only exception could be a bona fide employment contract or CBA that provides additional compensation or limits the hours you may work.

If the company is closed for an entire workweek, the employer is not required to pay for that week, although they can allow or require that you use any paid time off/vacation you may have available.
http://www.dol.gov/dol/allcfr/ESA/Title_29/Part_541/29CFR541.602.htm

Having said that, if I had an exempt employee who had been putting in excessive hours for months, but didn't have vacation/PTO to use for a full week shutdown, I would certainly pay something, maybe even the whole week, even if the law didn't require it. Not all employers will choose to do this, though.