As for actual lesson books, we highly recommend the the Japanese From Zero! series, which my wife and I wrote for our live classes in Las Vegas.  I honestly have not seen another book that I think truly makes it easier to learn Japanese.  Keep in mind we wrote the books because of the fact that we thought other books were either too hard or lacking in easy to understand grammar explanations.

There is also a REALLY cool Kanji book that you can get from Amazon.com called Kanji Pict-O-Graphix that I also highly recommend for an innovative way to learn remember the Kanji.

2. How can I make Japanese friends?
You will find that Japanese people are VERY friendly.  This question is easily answered.  Just start talking to Japanese people when you get the chance.  Japanese people are generally in love with the other countries and they also would like to be your friend.

Also why not consider signing up to host a Japanese exchange student.  This is a great way to get your foot into a family to family friendship.  And most likely you will want to eventually go to Japan.  If you have have hosted a Japanese exchange student then you will have friends in Japan to visit when you go.

Another idea that might seem radical is sending your child to a Japanese high school for an exchange.  I was able to easily find a school in Japan that welcomes all nationalities to their school.

3. How can I maintain my child's interest in Japanese?
This normally is not a problem if the child begged you to let them study Japanese.  Which is more and more common because of the coolness factor of Japan.  If your child is JUST studying the language then they are missing a big part of Japan.  And this is the pop culture.  The music, the TV, the comic books.  If you pay attention you can still keep your children away from the sometimes very adult natured items by researching what the want to buy.

Some VERY safe comic books are Doraemon and Obake no Q taro also.  Doraemon is about a robot from the future that helps his friend Nobita out of various situations.  It has been popular in Japan for over 20 years and is STILL interesting to years.  There are also movies and TV shows of Doraemon.  The Japanese is clean an the topics are never adult in nature.

Also Japanese music is a great way for your children to get more involved in Japan.  They can take the mainstream route and order from places like YesAsia.com or maybe if they want up and coming independent Japanese bands selling legal MP3s they can check out a site that I opened up supporting Japanese music called JapanFiles.com.  One of my personal favorite independent bands is Guitar Vader.  You can also see free Japanese music videos of them and other bands at JapanFiles.com.  BE warned that you might not want to show your younger children the Cool TAK - I am so cool video as it is a bit adult in nature.

I am also a big fan of Morning Musume.  There songs are always very positive and they are a great bunch of Japanese girls with great personalities.  Keep in mind there are TONS of options for Japanese entertainment.  These are just my personal recommendations.

4. Where can I get my Japanese questions answered?
There are a few places on the internet that will answer your questions.  One is http://www.japanese.about.com/ which is a GREAT free resource site.  I believe that they will actually answer questions submitted to them.

Also YesJapan.com has licensed native Japanese teachers on staff who answer questions submitted by our members everyday.  Every question ever asked is also available in a huge QA Database with over 1,700 answered questions.  If you can find a reliable way for your child to get questions answered this will REALLY help in the learning process.  This is why we feel YesJapan.com is one of the best ways for children to learn Japanese at home.