I wasn't really aware of a standalone program.
As far as I know, the ads where created online at their website, then pushed out to the unit through meganet. if your machine(s) where offline you were able to download the ad after completion and insert it to the system through USB.
I personally never used it because the website at the time was crap and most of the assets didn't load. (broken links and missing graphics.) made it frustrating and pointless to use.
not sure, but you can probably create something and manually chuck it in there as long as it was formatted correctly... I think mahkeymike was working off and on on some megatouch graphics stuff... maybe he can chime in.