Hi there. I don't blame you for not wanting to medicate your five year old. I would be very reluctant to do that as well, so I think it's good that you're looking into other options.
That said, I am compelled to say that it is extraordinarily trying and difficult to teach not only the child who has ADHD, but the rest of the children in the class he or she is a part of. Kids with ADHD have a tendency to either zone out and slip right under a teacher's radar because they're so quiet, or they are doing something disruptive every five minutes. And then there's the difficulty of discerning behavior that is a result of ADHD and behavior that is a result of a kid being a kid.
I hope you can appreciate the teacher's side of this- so I encourage you to continue to actively do everything you can to help your son manage the ADHD. I had a child, who I absolutely adored in my class several years ago whose mom refused to medicate, but she never did anything else either. The poor boy basically had a wasted year, because despite all of my hours and hours of extra work to support him in the classroom (charts, visuals, small group instruction, individualized instruction, alternative seating arrangements, and much much much more)his brain simply couldn't handle all of the incoming stimulus- not his fault. One frustrating side affect was that the constant checking in with him to help him along meant I was neglecting other students. A teacher never feels good about that.
The kids I've had who have been medicated still need extra support; the difference is that the extra support actually works.
Here are some sites that seem worth checking out. If either of my daughters were to be diagnosed with ADHD, I would do absolutely everything else possible before medicating, but in the end, I would medicate if nothing worked.
http://www.healing-arts.org/children/ADHD/mri-imaging.htm
http://www.akidjustlikeme.com/id92.htm
http://user.cybrzn.com/~kenyonck/add/Links/links_categori...
http://www.adhd.org.nz/neuro1.html
I just remembered one boy in my class whose parents told me halfway through the year that he had ADHD and was on medication. It came up because he had been having some difficulties in class and that was very unusual for him. Turns out he had gone off of medication. I would never in a million years have guessed that he was ADHD.
Okay, I've rambled on and on and maybe not said the things you want to hear...but I do wish you the very very best.
J.
Here's one more: http://www.schwablearning.org/
It looks really excellent.