Learning how to speak Greek.
Get Spiros Zhodiates modern Greek audio New Testament at Amazon, by typing in these exact words "Koine Greek New Testament by Spiros Zodhiates". Listen along to 1st John and a few chapters of the gospel of John several times, without reading anything. You just want to absorb these sounds. See my Jan. 22 post with an audio link to Zhodiates reading First John... http://www.ellopos.net/elpenor/koinonia/topic.asp?TOPIC_ID=219
Then, assuming you know the letters, do it again, following along in an interlinear Greek-English New Testament. Just mimic the way he says the words. You will not only learn a beautiful way to say Greek, you will pick up a lot of vocabulary words with little effort. (The Erasmian pronounciation sounds terrible.) Once you learn to speak it, Greek becomes more alive and you can hear it in your mind when you read it.
If you want to branch off into Classical greek, get a copy of the interlinear Greek-English Xenophon's Anabasis.
This is the Koinonia link to a pdf file of the beginning chapters of this
Look it up on Abe Books.com There are not many out there for sale!! This is a wonderful narrative that's hard to put down--this makes the work of learning Greek much easier. After going through the interlinear version several times you will want to transition to Loeb's text of the Anabasis--with Greek on the left page and English on the right. This is much harder--but you can make progess by checking what you think the Greek means by skipping over to the English side. You can always look up the meaning of individual words in the Anabasis at the "Perseus" Greek site. Note this: the interlinear gives you ready access to a large quantity of Greek, without knowing very much grammar. You can download the Loeb edition of Zenophon's Anabasis at Google Book for free. [Note: read below this post for a direct clickable link to this book.]