I get my positives printed at a local blue print shop in town. I have them print it on a transparent mylar and it's a really really good positive but it's expensive. I just did a 17x24 2 color print and the positives were $32...i think it's kinda bucky anyways.
I've heard people print on shit paper and baby oil it but that sounds like a mess.
What are the other alternatives to transparencies?