Volunteering in Asia forum

Hello!
I am currently planning my trip to Thailand, for next year (around November to January 2012).
I would be really interested in volunteering for a minimum of two weeks, anywhere in Thailand. I love working with children, and i would be particularly interested in working in an orphanage or teaching English!
I am having quite a bit of trouble finding something though, as many organizations are asking for huge fees... I have been told that these fees do not benefit the children, and that many organizations although they say are non profit, are actually not.

I understand that I may need to pay a certain amount for different things such as accommodation or food, and that is fine!

Finally, I am not yet 18 and will not be for the start of my trip, and quite a few volunteering website only accept over 18...

Your help is much appreciated!
Thank you!