[Junochan]

Hello, everyone. This is my first post on this site and I'm in need of help. I am a U.S. citizen (I'm a boy, just so you know) with a huge interest in Japan. I've been really interested in exchange programs and such, but I have not been able to find a possible opportunity... until now...
I finally have a chance to get a scholarship, along with 19 other people, for an exchange program (my mother says not to give out WHICH program, due to competition) to Japan... and there is alot of paperwork and stuff I need to do... but one of the things I need to do is write to a host family.
There are no specifics to writing to them, but I would prefer to be proper, especially for a Japanese family I don't know yet. When writing or typing a letter, is there anything that is specific to Japan? Or anything to start/close the letter (like a "dear host family", a "Sincerely", an "I look forward to meeting you", or something like that)...?
For my own Japanese language knowledge: I have tried studying Japanese on my own for the past few years and I know the basics of the spoken language, as well as the hiragana/katakana lettering. Kanji is difficult for me, though I have been recently making an effort to study it more (I don't have any Kanji-specific textbooks), so I'm improving in that category. I know more than the typical person at my school (though the school has no Japanese language programs and it tends to be anti-asian, hence the rarity of this program).
The one thing the application didn't say was the language the letter should be in. The program says the host country language is not necessary, so I assume I can write/type in english (even for me, it would be hard to write/type in Japanese formally to a native Japanese person). However, I still would like some tips.

Also, if anyone would be so kind as to tell me a bit of the daily life of the average Japanese family during the summer (or rather, around the end of June to the beginning of August or so). I have done my own research and I've also had previous knowledge of some things, but it wouldn't hurt to hear from someone personally talking to me. I'm looking for things like how someone may take a bath or how/when they sleep or even emergency numbers... Proper etiquette(sp?) would also be appreciated...
And as to whether I'd be going to a Japanese school, I'm not sure (I'm only 16, and will be throughout the whole duration of the program, so it wouldn't be uncommon). The program didn't specify that information, though I wouldn't mind either way.
If ANYONE AT ALL can help me with this, it would be VERY appreciated...! I am very excited and may be getting my hopes up, but if I am chosen for the program, I would likely be one of the most happiest people in the world. That's why I am requesting this help! Thank you all for reading and I hope I didn't mess up the position of this topic on this site. If so, please notify me.
If you'd rather talk through MSN or if you'd just want to talk in general, please tell me so in this thread and I'll give you my hotmail name and hopefully contact you within 24 hours. *bows politely* Again, thank you, and I'm glad I was able to join this community~!