I just booked a flight for late February through the US Airways Webpage ( www.usairways.com ) for 396 (all included) and that is for weekend travel-if you can leave during the week, prices start at 302 $ (plus tax) and the last travel date is early April. You have to book through the web, but I think you even get bonus miles for doing so.
I guess there are similar deals for other cities on the East Coast because it is a connection over Philadelphia anyway.
I checked Travel Agencies before and the cheapest they offered me was 480- far more than what you can get on the web. I can also recommend the Airfrance Webpage as well as www.cheaptickets.com and www.itn.net (they all had deals around 400, taxes included)

[This message has been edited by MadridMan (edited 02-08-2001).]

Low fares are available into the first week of April. I just booked through Yahoo travel on Iberia (New York - Madrid - Malaga)for $378. I leave on 3/26 and return on 4/3. When I contacted Iberia they quoted a price of $625. They do have a recorded message saying that lower fares may be available on the internet or through companion carriers.

Iberia did have a 2 for the price of 1 Valentine's Special for travel in February.

Have a great time in Spain.