US citizen travelling between Schengen Countries

[swimmingupstream]

I am an American. I have been in France since late April 2008 until the present, beginning of November 2008. I realize that I have outstayed the 90 days in 180 that I as an American may stay in a Schengen country. However, I would like to leave France for a few weeks to visit a friend in Italy, also a Schengen country. My question is thus: will I be obliged to pass through Immigration and present my passport upon my arrival in Italy and/or upon my return to France? And if so, will this be problematic? Would it make any difference if I travel by plane or train? Thanks in advance for any advice you have!

[vinny]

Travel without internal border controls within the Schengen countries. Temporary reintroduction of internal border controls possible. The visa limit is applicable to all countries within.

[swimmingupstream]

thank you Vinny.