Hi Karen
If you have loads of time, trawl through the archives of Henriette's herblist as the use and preservation of ceder resin is discussed from time to time, usually during the winter months.
I would also check through the books and sites of Scandinavian and Canadian herbalists who have large stands of cedar to call upon. There was something in Ray Mear's latest series on bushcraft across Canada which had to do with the use of cedar.
A couple of things I remember from discussions is that cedar resin doesn't dissolve in alcohol so you can't make a tincture from it. (Several years ago, someone in Nova Scotia sent me some resin and the first thing I did was cover it with vodka and wondered why nothing happened!) It's also fantastic for burns - you can slather if over a new burn and it forms a seal which keeps out the air and other nasties. New skin can then form without any scarring.
I'm sure Katrina has posted something about cedar on her blog
http://herbalmatters.blogspot.com/) - she has family in Scandinavia so it's a normal part of their herbal retinue. She hasn't posted there for ages, so I'm guessing her new job at Kew is keeping her very busy.
Hope this gives you some ideas! Let us know how you get on with the resin.
Sarah