Hey LJ...
quote:
"...but someone I know there does not want to leave Spain for life here."
... sanity prevails!
Anyone will tell you that I am the first person who would be willing and ready to give the old "throw caution to the wind and come on over" advice, you know, leap before you look

It is easy for me with a British and American passport so I must admit that my advice can be a bit hasty at times.
quote:
"I'll probably be moving over to Madrid, maybe for good, but not without a job already guaranteed".
Yikes! Sorry to say that this is next to impossible

It is VERY, VERY, VERY, "MUY" hard to get a job over here while still abroad. Not impossible but pretty close.
Things are VERY difficult here for non EU nationals these days and are getting tougher every day
99.999999% of the people I know over here found their jobs AFTER they arrived, many had tried before coming but were frustrated by the search and the difficulty of it all.
Sure there is always that .0000001% who got the sweet job offer before they came or who were transferred here by there comapanies, God bless, more power to them but they are the super "afortunados" (fortunate) ones indeed
quote:
"I suppose to get into a better teaching position for English, English Lit., Is my Spanish grammar Qualifications going to require very extensive knowledge of Castillian language?"
Well, in my humble opinion, if you are going to teach English lit here it will probably have to be at a University so aside from the usual required Doctorate

, you will definintely need good spoken Spanish (although perhaps not an in-depth knowledge of grammar). There are also private schools (high schools) that may also hire without a Doctorate but I am afraid they may require a high level of Spanish and you will have to be legal here.
Yes, you should start by asking your questions at the Spanish Embassy there. As far as dual citizenship goes, no agreement exists between the U.S.A. and Spain, it is one or the other. You need not think of dual citizenship just yet, that is a bit extreme to come over here, start by trying to get a job offer that will give you legal residency and working papers. See the many threads on getting a work visa and such on this work and residency in "espa�a" forum for more info.
I know loads of expats who live here and none of them have given up their American (or other) citizenship for Spanish citizenship, that is a VERY serious move.
Saludos & Suerte,
jer...