There are a couple of choices if you want ot go the retail route. One is a flat case, that carries them folded in half. Obviously if you don't want to go the retail route a couple of pieces of cardboard and a couple of rubber bands would serve the same purpose.
ebags has several:
http://www.ebags.com/Travel_Accessor...sub_site_ID=24
The other choice is a tie roller that I've seen in catalogs, but haven't purchased yet, though they do intrigue me. An example is at:
http://www.etravelergear.com/tiecaddy.html
Me, I roll them up and stuff them in my shoes, and if necessary iron them when I get there, thougn someday when I'm ordering something else from one of the catalogs I'll toss in a couple of the roll up things.