Just so everyone is aware. If you buy a used Apple TV (lets say 40GB size version) the software is likely to have reverted to version 1. As that is what is re-installed when the apple tv is fully reset.
You need to let the apple tv download the latest version of software (like 3.x something), from the remote apple web site, so that the ATV Flash can actually work and install after that.
Of course there is nothing anywhere clear on this ATV Flash web site saying that.