What is it?

What, not where, WHAT the hell are ISO's, and why can't we ask where we can get them from?

[Wayne]

ISO is a generic name for a CD image file. In this case, it refers to Dreamcast game CD image files.

The reason you cannot ask where to find them is that it's against the rules. The reason it is against the rules is that it could lead to legal complications with this message board, which could in theory, even lead to it's being shut down. For the most part only information is #####d here, with the exception of where to find game copies. If you're still wondering where to find games, perhaps a quick search in a web-browser or news-reader wouldn't hurt.