I just sold my saddle on eBay..and I've never shipped one before. What do I wrap the horn with, bubble wrap? Do I put anything in the box with the saddle like shipping peanuts? 

I pack as much stuff into the box as possible.  This will keep it from rattling around and poking through.  I also make sure I wrap the horn well with an old tshirt or something. 

I wrap horn and stirrups with bubble wrap and saran wrap so they don't get rubbed and rub anything. Then stuff open areas of box with shipping paper, peanuts, etc. My husband has a company with a shipping department, so they usually do it for me. 

I wrap the entire saddle in bubble wrap and secure it with packing tape. Usually I put an extra layer on the horn and cantle.