Probably any gallery that's used to dealing with 
fine art will be a good place to go to. They'll 
be aware of archival considerations, and will 
also take into account the medium. While I know 
some people who were very good, careful, 
considerate framers who worked for craft stores, 
they had horror stories about other framers who 
weren't quite so good... :o) You want to deal 
with people who are used to handling expensive 
art, rather than high school students working 
over vacation. :o) 

On your part, you'll want to make sure that you 
hang it somewhere that does not have direct 
light, has a stable temperature, and does not 
have excessive particles in the air or moisture. 
(Not in the kitchen, not in the bathroom, not 
around smokers... You'd think people would know 
better than to hang their good art in the 
bathroom, but then you hear stories that change 
your mind!)