Southwest will begin servicing New York's La Guardia airport June 28, 2009, and they are offering a $99 special deal to introduce everyone from Albuquerque to West Palm Beach to their new destination (yes, of course Los Angelenos can take advantage of this deal too).
As with all great deals, there are certain rules; you must book by April 20, travel June 29-August 13, and you can not fly on a Friday or Sunday, or July 2-6th on this fare. All taxes and fees are not included, and you can not combine this offer with senior or group fares.
If you don't want to go to NYC, or want to get away right now, Southwest also has last minute $99 fare deals from LA to nearly all their serviced cities, like New Orleans, Seattle, or Lake Tahoe. You just have to purchase 7 days in advance, and by April 13 for travel by May 21, 2009, and you can travel every day except Friday and Sunday. For an even cheaper getaway, try Phoenix for $49 with a 14 day advance purchase (this offer also excludes Friday or Sunday travel).
At these fares, if you have a choice of flying or driving, flying is clearly the best choice (unless you are moving).