Most cruise lines will sell you airfare too, however, you can often find better pricing if you do air on your own. It's always a good idea to ask the price of the cruise line's airfare and transfers, so you know how to evaluate your own research.
Airfare generally becomes available about 330 days prior to travel. Airfare for November 2010 should be out sometime in January 2010.
If possible, it's a good idea to fly to Ft. Lauderdale the day before your cruise departs. This gives you a little extra wiggle room if there are airline delays due to weather, mechanical delays, schedule changes, etc.
If you fly to Ft. Lauderdale the day your cruise leaves, the earlier the flight, the better. You can get onto the ship as of about noon or so, and start your vacation then. You HAVE to be checked in at the pier no later than two hours prior to sailing.
For departures, if you're flying out of Ft. Lauderdale from a ship that comes into Ft. Lauderdale, they generally recommend that you plan a flight that leaves no earlier than 11:30am or so. Again, check with your travel agent or with the cruise line for specific recommendations.