Trivium Pursuit's Books about Biblical and Classical Greek
This site has a number of resources for homeschooling Greek. The following resources can be found there:
Bluedorn's A Greek Alphabetarion: This is a primer for how to read, write, and pronounce Ancient & Biblical Greek.
Bluedorn's Greek Alphabet Banner: This is a banner featuring the entire Greek alphabet that can be displayed on a classroom wall.
Bluedorn's Greek Alphabet Flash Cards: Each card has on one side one Greek letter (lower-case and upper-case) followed by its correct pronunciation on the reverse side. These correspond to A Greek Alphabetarion.
Bluedorn's A Greek Hupogrammon: Though the lessons in this copybook can be used without any accompanying text, they are designed to correspond with the more extensive textbook, A Greek Alphabetarion.
Bluedorn's Homeschool Greek (Vol. 1): This is a self-contained Greek course written by Harvey Bluedorn for students ages thirteen and up. The Volume I course, “Mostly Nouns and Such,” consists of a 310-page, plastic comb-bound textbook, a 65-page Greek reader, vocabulary cards, and three audio tapes. This grammar does not begin with the alphabet and pronunciation.
Bluedorn's Little Baby Learn Greek: Using 27 original illustrations, writer/illustrator Johannah Bluedorn offers a pictorial lesson in learning the Greek alphabet. Each Greek letter is introduced on a separate page of the board book. The sound of each letter is taught with an English guide word and a corresponding picture.
Bluedorn's A Review of English Grammar: This book shows the relationship between Greek and English grammar.
Gibbs' Adjective Piggy Bank Game
Match Greek adjectives to their English translation and collect coins.  
Karen Mohs' web-site is aimed at introducing Greek, especially to children. This provides an enjoyable means of learning the alphabet and picking up some vocabulary. Her Hey Andrew! Teach Me Some Greek (Grades 1-8) introduction to New Testament Greek begins with The Reader, which uses a picture book style format and catchy rhymes to teach the Greek alphabet. After The Reader, Karen Mohs' materials (Levels 1-8) correspond to the grade level of children. Each level has the following materials available like: Reader, Workbook, Answer Key, Quizzes/Exams, Flashcards, Pronunciation CD (or tape), Music, and bookmarks. Her Super, le Grec! is Greek grammar material for French-speaking children. Currently only two levels are available.
Friedrich's Deaf Pah! Greek
This course is designed for hearing-impaired students of New Testament Greek. The course is designed using Moh's Hey Andrew! series and features supplementary materials online, such as the sign language alphabet chart (very cool!), flash cards with hand signals, etc. 
Harry Foundalis' Greek Handwriting
Learn how to write all the Greek letters with this helpful illustrations, showing starting and end points. 
Marcos' "Leveled" Readings from the GNT
Marcos has a thread on the TextKit forum where he is taking passages from the NT and changing words with few to no appearances in the NT for words that occur 50+ times so that children can practice Greek from the New Testament. 
Mounce's Kids' Greek
Bill Mounce and Ed Taylor have developed a Greek resource for teaching biblical Greek to children from grades 3 through 8. This website is dedicated to teaching students how to study the Bible better. Not only will students learn the alphabet, verbs, nouns, etc., they will also learn how to use Greek dictionaries and concordances.
Perrin's Greek for Children
Classical Academic Press has published Greek for Children Primer A by Christopher Perrin. It is comprised of thirty-two chapters, to be completed one per week. Each chapter will begin with a memory page, presenting the chant and vocabulary for the week’s lesson. Grammar lessons are presented at the student’s level on the grammar page, and each chapter includes a worksheet and a quiz. An answer key for exercises, flash card tool, and audio recordings are available at this site. Be sure to see all of the related products available. A sample DVD of the Greek curriculum is available here.  
Perrin's Greek for Children Alphabet Song
This alphabet song is a supplement to Classical Academic Press' Greek for Children Primer A by Christopher Perrin.  
Rozalowsky's "Will You Teach Your Kids the Languages?"
Andrew Rozalowsky discusses his train of thought for teaching the biblical languages to children. 
Schoder and Horrigan's A Reading Course in Homeric Greek Book I
Using Homer's Odyssey in this beginning Greek grammar, daily lessons are arranged so every word, form, and rule in the day's selection is learned beforehand. The book also includes various aspects of ancient history, Greek culture, art, sculpture, architecture, democracy, and the dawn of Western Civilization highlight humanistic values.
Schoder and Horrigan's A Reading Course in Homeric Greek Book II
Using Homer's Iliad, each lesson is a passage consisting of ten to twenty-five lines of text. Each lesson also includes a memorization list of frequently found words, thematic commentary in shaded boxes, and expanded and revised grammatical notes. The text also includes a Greek-English vocabulary list, an appendix of a summary of grammar, and an appendix on reading Homer rhythmically. 
Teaching Proficiency through Storytelling
B-Greek has a nice thread on how TPTS can be used to teach children Greek.
The Little Greek
A frequent poster on B-Greek forum, Jonathan Robie, provides this Greek website on learning Greek and helpful resources. His online Greek textbook (in progress) is found here
Where Are Your Keys? Techniques
Some on the Internet have recommended this website and philosophy for teaching children Classical Greek.      
Wright and Pharr's Homeric Greek: A Book for Beginners
This is John Wright's revision of Clyde Pharr's original text, which emphasizes beginning with Homer instead of Attic Greek. It is designed for high school or college students