I have a 10-year old son who was diagnosed with ADHS a year ago. The first thing the therapist suggested was medicating him. The main thing with him is that he can't stay focused on his work at school or homework. He constantly figits and his mind is in la-la land. When he is focused he does extremely well but I have to sit with him like he's 3 to keep him focused. Should I put him on medication during the school year or just keep working with him like I've been doing? And what changes would he go through when he's not medicated if I decide to go there?

You should also study up on things you can do and try them if you do not want to start him on meds. IF he still is having problems when he gets back to school they could insist that he be medicated.

Read
The Crazymakers by Carol Simontachhi
And Brain Allergies by Dr Philpott

Cut him off ALL junk food and preservatives possible.
Give him omega fatty acid like this OmegaBrite | OmegaBright: 100% natural, advanced Omega-3 formula (http://www.omegabrite.com/OmegaBright.html)

Also some people swear by this Hyperactive Children - Homeopathic Remedy for Hyperactivity (http://www.nativeremedies.com/products/brightspark-hyperactivity-in-children.html)

If and when you give him a prescription medicine it would be given so he is always medicated.
If after awhile he seems like the meds aren't working you need to take him back to the dr for re evaluation
And they will up the dose or switch him to something else.