http://www.amazon.com/Garden-Auger-Bulb-Planter-Regular/dp/B000WFKCPQ
One of these, a good cordless drill, and a lot of batteries or a FAST charger. Easier to handle than a motorized post hole digger if it can handle your soil, but the engine driven one is faster in tough ground--it is just a two person job most of the time. Get the small planting auger, not a big post-hole auger, if you rent one.
If your ground is JUST RIGHT you can stick a tiling spade down, rock it back and forth, and pull it out to have a V-shaped hole just big enough for bare roots. Step around it and it will close back in on the roots.
"You must be the change you want to see in the world." "First they ignore you, then they laugh at you, then they fight you, then you win." --Mahatma Gandhi
"Preach the Gospel always, and if necessary, use words." --Francis of Assisi.
"Family farms work when the whole family works the farm." -- Adam Klaus