FMLA is something you apply for at work through your HR deparment and involves paperwork and information from you doctor(s) to support your leave or intermittent leave for a serious health condition. It's important to get the paper work completed in the time allowed. It is job protection. It isn't income protection like short or long term disability so it isn't paid leave. It is confidential and between you and your HR department.

There is more info here: http://www.dol.gov/whd/fmla/index.htm