I couldn't conjure up the picture, but i think you are describing a "Post-hole digger". If it has two long wooden handles, and a half bucket type thing on the end, hinged so they sit opposite of each other, on the ends of the handles--yep--thats a post-hole digger! A good tool for the purpose, but if you have a lot of holes to dig, it might be better to rent a powered post-hole digger.
Pre-dug post holes are available from some place in the Kountry Life section, but i'm not sure of the cost or availability! by: Rusty Jones

It's called a drain spade.

I couldn't find a drain spade picture to match what the OP posted.

What searches call a drain spade is what I call a transplant spade.

http://www.uniontools.com/product.asp?Cid=1&Cat=2&Brand=&Query=&Page=2

http://www.ridgid.com/Tools/16-Drain-Spade-Shovel/EN/index.htm

I have not seen anything like that before. I am guessing based on the company you link to that sells that tool plus the design that it is meant to be a type of post hole digger. The company seemed to be a fencing company. The tool looks to have a long heavy handle similar to a landscaper bar. The small head and curved/bent sides along with the heaviness (assumption) would make it suited for using the tool going up and down like a post hole digger. If it is heavy you could go us it near horizontally but it would be less efficient if it is as heavy as I think.

Page 5 of this catalog shows the same type of shovel along with another landscape type bar.

http://www.fedimecc.it/pdf/2004/13%20AGRICOLT-GIARD%20162-169.pdf

This is a picture that the OP posted.

{{gwi:308945}}

Does look like some type of spade. Not a post hole digger of which there are two basic types. The Clamshell which is most popular and the Boston digger which has a single blade for digging and a clamp for pulling the dirt out of the hole. With any post hole digger you have to have some means of pulling dirt up out of the hole.

Here is a link that might be useful: Post hole diggers