you can shoot them with your slingshot, this way they will be paralized for a few seconds then you can run up and attack them from behind

While they hold a bolder over their head try shooting them with the slingshot. They will then crush themselves

I just ran up there.

http://www.youtube.com/watch?v=YfwYfoK2zJM&feature=relmfu

you mean this right?
you also can just run up there, when one of them has no boulder in his hands. (the part begins at 30:04)

Actually, you CAN just run up there. If you're between two of them, they kinda just stare at you while you climb up the wall.

Or, you can wait until they grab a rock, you hit them with a slingshot, and the rock falls, crushing them.

Yea like some have said i crushed them with the rocks they were holding using the slingshot.

This.

The first one I met I did it by timing it right, if you run up then dodge the boulder he throws, and get up the ledge while he goes to get another.

When I got to the bit where there are three of them I shot one with a slingshot whilst he waited with a boulder above him and he crushed himself, then I ran up in the gap I had made and killed the other two.

If you hit them while the boulder is directly over their head, they drop it when they get stunned and it lands on their head and they die. I found that by dumb luck (was trying for a stun and run).

I used the Beetle like you (same as in other areas in the Temple), but you can also use the Slingshot, or simply run up there.

Whatever floats your boat.