Hello (future) rooters.
I've placed your queries in the new All Things Root sub-forum for the Iconia 500, where you'll find the (new) Root Guide for that device.
Iconia Smart: All Things Root Guide
At this writing, the root exploit has not happened for the Iconia A500, so that Guide is rather sparce of info (read: no root info specific to that device
But, please be patient; at some point all Android devices get the root exploit and we start seeing posts/threads about it and we'll begin to populate that Root Guide with the info.