Curiously during the last couple of days I have received several questions about books and tutorials about Smalltalk. If you are starting with Smalltalk I strongly recommend you to start with “Squeak By Example”, you can download a free .pdf copy from here.
If you need some in Spanish I recommend the book by Diego Goméz Deck, that is available here.
After you had understood the basic concepts I think that two mandatory books are the ones by Adele Goldberg: Smalltalk-80: The Language and its Implementation and Smalltalk-80, The Interactive Programming Environment.
Finally in this page you will get several links to free online books
Hope this help.