Uz-Translations, Turkish section. Textbooks, various written materials and movies you can download.
Basics of Turkish Grammar by Bob Cromwell, a person who traveled many countries, including Turkey. Brief and comprehensive explanation various grammar rules and suffixes; a good reference.
Manisa Turkish. A site with detailed explanation of grammar, with many examples. Also features a section of Turkish tests to check how advanced your knowledge is.
People to practice with
LiveMocha. There are lessons in many languages, including Turkish. Exercises are conducted via flash cards – simple, but they can be used for polishing grammar basics and getting used to pronunciation. The big plus of the site is a vast number of native speakers in many languages, who review tasks completed by other users.
Italki. Community of people studying foreign languages.