Hi Jenny...
Just wanted to comment on your post. I taught over in Spain awhile ago (3.5 years ago to be exact) and I'm also American.
The truth is, Spanish Academies and Institutes, but most private schools DO prefer EU nationals because of their legal capacity to work in Spain. But any American determined to teach English in Spain will know that the demand for English native speakers in Spain is SO HIGH that many schools/academies are willing to hire us(under the table) regardless of our illegal work status.
Go with caution, but know that it's a very popular road and that MANY Americans, Canadians and Australians have all worked fairly successfully without any working papers.
Hopefully soon, and this is a RUMOR, there might be an alternate route for us North Americans to work for a time in Spain with legal working papers (sort of like what Council Travel does for France, England et al.)
Until then, your desire to work in Spain must be seen as more of an adventure than a sure thing. Bring back up funds and lots of resources to help you gain employment (local newspapers, classifieds, etc.)
Your most important resource is the people you meet...other Americans in Madrid struggling, looking for work just like you can help out a lot!
For immediate resources try the following:
http://madrid.edreams.com http://www.MadridMan.com http://groups.yahoo.com/group/spain-english and COMING SOON...
http://www.ExpatriateCafe.com And as for age discrimination in Spain, yes, I too have heard about this but cannot verify it. A positive attitude might combat that stereotype right off the bat!
Good Luck!
Tracy