I'm not sure whats going on, but both of my two front tire (the inside) are wore down. Any help will be apreciated.

 

You should check your alignment. You probably have to much camber.

As a result, only one side of the tire is touching the road...

 

actually usually the toe is way out of spec, camber sets "where" the tires wear, the toe determines "how quickly" they wear. a good alignment will fix you up.

 

My tires started to wear out at about 10000 miles. Is this normal?

 

That depends on how your driving style. If you launch alot, do burnouts, or corner hard often then 10k miles isn't abnormal. The stock yokos have a prety low wear rating for a street tire. Also, did you rotate your tires every 5k miles?