The 100th Infantry Battalion (Nisei) was assigned as 2nd Battalion, 133rd Infantry Regiment, 34th Infantry Division at such places as Salerno, Cassino, Anzio, and Rome. They were later assigned as the 1st Battalion, 442nd Infantry Regiment (Nisei). The 100th was and is permitted to retain their ordinal number, and still exists as the ONLY Infantry unit in our National Guard, and are stationed in Hawaii.
The 442nd was assigned or attached to the 34th, 88th, and 92nd (Negro) Infantry Divisions at various times and places in Italy, and to the 36th Infantry Division in Southern France. (Think back: who rescued the "Lost Battalion" there?) The 442nd Regimental Combat Team consisted, in the main, of the 442nd Infantry, the 232nd Combat Engineer Battalion, and the 522nd Field Artillery Battalion.
On medals awarded, the 442nd received 20 Congressional Medals of Honor, of which 8 went to the 100th Battalion. For a quick overview of MOH recipients in the Mediterranean, see
http://www.milhist.net/mto/moh.shtml
For a excellent presentation of the 442nd's history see
http://www.homeofheroes.com/moh/nisei/index.html
For a short piece of more recent history, see
http://www.34infdiv.org/feature/lastparade.html
The 442nd will have their 60th Anniversary Reunion in Honolulu in April.