How it works: Airlines collect additional information for each passenger and pass this information on to the government. Once received, names are reviewed to ensure those on government no fly lists don't make it on board, and to determine which travelers who for enhanced airport screening. This information is then transmitted back to the airlines.
Information you will need to provide the airline: Full name, as it appears on government-issued I.D when traveling; Date of Birth; Gender; Redress number (if applicable).
Secure Flight is currently being phased in with each of the airlines - not all airlines require it yet. But if you have upcoming reservations it's a good idea to check those itineraries and provide any requested information in advance.
Here's a 90 second clip from TSA with more information on the program.