Amazon, Home Depot, Radio Shack.... Go here: http://www.apexhandtools.com/brands/weller/ and click on the where to buy button at the top of the page.
Me too! Mine's over 30 yrs. old and still going strong! Despite my accidental drops that should have destroyed it!
Look in second hand tool shops. They almost never break. Estate auctions and yard sales are another good place to look..