Question:Thanks for getting back to me. If I wanted to learn more about the Koine Greek, what would be a good starting point or book? Is the one you quoted good? I am literate in Spanish and know the commitment to learn another language. Would you be willing to give pointers if you know Greek?
William D. Mounce's book Basics of Biblical Greek Grammar is an excellent choice. It is the best one that I have found so far and he did an excellent job of simplifying all the possible case endings into a few relatively simple charts. The book also comes with a CD with practice sessions and Mounce's lectures. There is also a workbook to go with it.
Another resource for learning is NT Greek .Net. This is an online course that is run by a fellow preacher, Jeff Smelser. I've heard a lot of good comments about this course, though I haven't taken it myself.
There is another online course called Introduction to Greek that is also run by a fellow preacher, Don Martin. This course is free. Again, I haven't taken the course, but I have heard good comments about it.
I consider myself still learning Greek and not at the level necessary to teach it to others. I would, instead, urge you to take either Jeff Smelser or Don Martin's courses. Either man would be far more capable of answering your questions.