downtown, southside, good family oriented red sauce italian

I need a place to take a Thai visitor with his family for american style italian food, in the downtown area. any recomendations?

I don't think you'll find anything downtown other than "faux" neighborhood, touristy places such as Maggiano's and (argh) La Cantina in Italian Village. Lots of good midlevel and upper level Italian choices in the area, but for the real "neighborhood" thing you need to leave the area for, well, a "neighborhood." Not too far away, only a short cabride, would be my favorite, Tufano's Vernon Park Tap. Here's a short write up:

http://metromix.chicagotribune.com/sear ... 2219.venue

A little bit further afield are Sabatino's and, perhaps, Scarola's. Search these names on the board for a lot more info.

Club Lago, maybe...

http://www.clublago.com/

It's pretty much "in" the Loop, and it's Italian American and very Chicago-y.

Bombacigno's, in the SW section of Downtown (West Loop, actually) might interest out-of-town guests; you'll be hard-pressed to find something more laid-back and "neighborhood Italian."

Bombacigno's
558 W Van Buren St
Chicago, IL 60607
(312) 663-4114

Another place I like is Bertucci's - in Chinatown (of all places!); it's very "neighborhood Italian" and it's easy to reach by taxi or public transport from Downtown (and the friends could wander the various nearby Chinese/Asian shops before/afterwards).

Bertucci's
300 W 24th St
Chicago, IL 60616
(312) 225-2848