I’m kinda-sorta planning out a road trip vacation, and one of the things on my “stuff to do before I die” list is to hear a chorus of timber wolves in the wild. Is there anywhere in North America, that is relatively accessible (by road, at least), that I could visit and be reasonably sure of hearing such a thing?
Algonquin Park, a hundred miles or so north of Ottowa (that’s in Canada, for my fellow USers 
). Stop by the side of the road after dark, get out and howl. The wolves will howl back at you.
The rangers actually run demonstrations to show you how to do this.
you could always go to a wolf rescue park?
There are wolf sanctuaries all over, where you might call for nothing more than information they might have on parks where you might hear them. I wouldnt recommend camping out in the wild hoping for a pack to run by and serenade you. Because while that might be one dead sexy addition to a great date, i doubt youd want it to be in the literal sense, aye? 
Maybe some of these urls would be of use somehow - and good luck!
Yellowstone Wolf Restoration Project <~~ check this more in depth, ive heard really amazing things about the work and education they do with the public on wolves.
http://www.nps.gov/yell/nature/animals/wolf/wolfrest.html
Northern Colorado - www.wolfsanctuary.net/
Antelope, California - www.nevercrywolfrescue.com/
And here’s a small list of sanctuaries and wolf related thingies - most of the URL’s i did find ended up being broken.
I used to be a wolf docent in a wildlife park. Our wolves came from Wolf Park in Indiana. They have a good wolf education program there if you get hooked.
You wouldn’t be studying them in the wild, but you would be able to have some actual contact with them.
http://www.wolfpark.org/seminars.html
(Welcome to the pack!)
Not too accessible (up near the top of the world), but if you hang out at my cousin’s place you’ll hear wolves. You never know just what will turn up at his front door:
http://my.tbaytel.net/culpeper/Go%20away%20this%20spot%20is%20taken.jpg
http://my.tbaytel.net/culpeper/Arctic%20Wolves.jpg
Short of that, I second BrotherCadfael’s recommendation for Algonquin Park. I’ve been there many times, and usually have heard wolves. My friends who have attended the guided wolf howling interpretion programs have greatly enjoyed themselves.
http://www.algonquinpark.on.ca/nature/mammals/wolf_howling.html
You could try Superior national forest in Minnesota.