Reply #9: Ok [View All]

Chang and Keisler is the standard textbook, but you'll have to buy it or borrow it from the library.
I browsed around to see what's available online, if I find anything better I'll post it later.
Google Books has the introductory pages from a couple of books on model theory:

Model theory By Chen Chung Chang, H. Jerome Keisler http://books.google.com/books?id=uiHq0EmaFp0C&lpg=PP1&pg=PA1#v=onepage&q&f=false

Model theory By Wilfrid Hodges http://books.google.com/books?id=Rf6GWut4D30C&lpg=PP1&pg=PR9#v=onepage&q&f=false

Wilfrid Hodges has a "Short model theory course" http://wilfridhodges.co.uk/mathlogic01.pdf
and other interesting things on his website http://wilfridhodges.co.uk/

The book Fundamentals of Model Theory by William Weiss and Cherie D'Mello is available here: http://www.math.toronto.edu/weiss/model_theory.html

Here's a another book online free that looks good:
MSRI Publications -- Volume 39
Model Theory, Algebra, and Geometry
Edited by Deirdre Haskell, Anand Pillay, and Charles Steinhorn
http://www.msri.org/publications/books/Book39/