To send a letter and recieve an autograph from your favorite star follow the instructions below...
If you live in United States send a properly stamped and self addressed envelope (minimum size 8.5" x 4") with your request letter and a photo.
You can include a piece of cardboard to keep the photo from bending in shipping and also add "Do Not Bend" on the envelopes.
Send your letter and wait. On average, there is going to be a 3+ month wait for a response.
This information was provided by fanmail.biz. You can go to that site for even more stars addresses.