Am in italy without documents and my visa is expired. My girl friend wants us to get married but she is an american can we be married? If not how can I get llegal documents so we can get married.

Why bother... under the current Italian Immigrations laws... getting married isn't going to change your status from being illegal. All it does is complicate your lives.

They did away with marriage making you elligible many years ago...

How do I know this? I'm one of the people grandfathered into the OLD law... there were too many people abusing it so they cracked down making it much , much more difficult.