I like using mortar, but I LOVE laying dry stack stone––not that I'm good at it––but it's one of the things that's the best therapy for me. I know that's probably weird, cuz I'm female, but I love building rock walls. I've found a couple of really good references at Barnes & Noble as I was just poking through the books in the home improvement section.
Here are the links on Amazon.....
This is one of the better ones––I don't own it, but I've read it three times sitting in the bookstore. I think I'll order it since there are some used ones on Amazon now.
http://www.amazon.com/Art-Craft-Stonescaping-Setting-Stacking/dp/1600591302/ref=sr_1_2?ie=UTF8&s=books&qid=1227299745&sr=1-2
I also liked this one:
http://www.amazon.com/Stonework-Techniques-Projects-Charles-McRaven/dp/0882669761/ref=sr_1_6?ie=UTF8&s=books&qid=1227299745&sr=1-6
And I think this one was pretty good, though it's been a long time since I looked at it.
http://www.amazon.com/Company-Stone-Dan-Snow/dp/1579653472/ref=sr_1_9?ie=UTF8&s=books&qid=1227299745&sr=1-9
There are others. Cruise your local bookstore if you haven't done so.
The things I learned from these books––the first one especially––were the following:
a) Importance of a good base––the right base––deep enough and wide enough for the HEIGHT of the wall you're going to stack. They talk about bases of concrete––an actual footer––as well as bases of nothing but gravel. They talk about the structure of the soil you're building on––all these things play into what you're going to do and how you do it.
b) Width of the base of the wall. A ten-foot wall needs to be fairly wide at the bottom––you have big pretty rocks on the outside and fill rock on the inside (with tie rocks that run all the way through every now and then, like one of the posters above talked about) ––the outer sides of the wall slope inward toward the "fill"––okay does that make sense?
c) They show different types of walls––for instance if you're in an area that has extremely high winds, you may want to build a type of wall that has holes in it––and there are ways to do this––to decrease the wind resistance. Or you might not.
There is a lot to learn about laying stone.
I am no stone mason, and no expert. I simply have this kind of funky weird connection with rocks and I love laying stone. I haven't built anything NEARLY ten feet high though––four feet is as high as I've gone. I dunno if I'd do a wall that tall without mortar. If you're going that high, it needs to be RIGHT, with or without mortar, so it'll be strong and stable, not create a danger to people near it, and it'll be there centuries from now.
These books even give tips on finding and moving stone without the big equipment most modern contractors would rely on. They range from the old fashioned ways of moving stone that were used before mechanization––all the way up to modern stuff, and they'll give you the math to use to figure the width of the base and the necessary "lean" or "slope" of the wall for the height.
I hope this is helpful. I didn't see many other answers, and I know there aren't a lot of folks out there now doing dry stack. These books talk about using mortar as well as dry stack, btw.
Dry stack is almost a lost art.
I have a wall that needs building too––but alas, neither time nor energy to do it right now.
I may be the only female in the universe who once asked for an Estwing Mason's hammer for Christmas.