He is a lawyer now. I am not sure if he will still sign or not. The address that I found is:

Case Western Reserve University School of Law
Attention: Charlie Korsmo - Assistant Professor
11075 East Boulevard
Cleveland, OH 44106-7148

There is also an email address which is:
crk64@case.edu

Did anyone ever write to actor Charlie Korsmo ? He was a child star -
He was in "What About Bob ?" "Hook" and "Dick Tracy" - I can't seem
to find an address where I can write to him - I am a big fan of him.

I know he doesn't really make movies anymore but if there is a way
I can send him some thing to some kind of an address that would be
cool.

Hope you can help me on this one -
Thanks