Some resources for learning Greek
There are several good books. The textbook by John Dobson has been recommended by a number of people. Its title is Learn New Testament Greek. Also, the following textbook is used in a number of Greek classes:
Mounce, W. (2003). Basics of Biblical Greek Grammar (2nd ed.). Grand Rapids: Zondervan.
Most people find it difficult to learn a language by themselves from books. If at all possible, you should be part of a class, whether it is held at a church, local college, or wherever. Another possibility is to take one of the New Testament Greek correspondence courses, where you at least have a teacher interacting with you, which helps.
Here is a url for a Moody course:
For on-line Greek course, try this:
You can also comb through the archives of the Biblical-Greek (B-Greek discussion list. They has some recent messages about resources for learning New Testament Greek:
You can even subscribe to the list and ask your questions there. There are a number of Greek teachers and others who are advanced on that list who could help you with information for getting started.
Hopefully, others of you will add more ideas in the comments to this post.