They're called signatures, and various people in the Museum make them. They cost TBT, or the forum currency. My friend A r i a n e has a very successful signature shop, and she only charges 30 TBT. Here's the link:
http://www.belltreeforums.com/showt...;-(on-family-week-end-see-post-1589-for-info). It looks like you have 12 TBT right now, but you can earn more by posting.