Here's a list from Steve's site regarding all the units that participated in the Italian campaign.
Marion gave you the link to my page on AOL. I've been moving everything over to custermen.com and updating the pages. This may have more info.
http://www.custermen.com/ItalyWW2/ArmyOrg/...g/AlliesOrg.htm
Before the veteran infantry divisions began to leave, more troops began to arrive just before the May Offensive and then after the fall of Rome. The 88th Infantry Division arrived around March 1944, followed by the 85th Infantry Division soon afterwards---both were the first all-draftee divisions.
Elements of the 91st Infantry Division arrived just before the fall of Rome in June 1944 and the remainder later.
The black 92nd Infantry Division was moved into the line in early fall and were hit by a German counter-offensive in December 1944. The Japanese-American 442nd Regimental Combat Team returned from a short tour in Southern France with the VI Corps and was assigned to boost up the 92nd Division. An anti-aircraft unit was re-organized into the 473rd Regimental Combat Team and also assigned to the 92nd Division.
By later winter and early spring 1945, more international troops arrived to join both the US 5th Army and British 8th Army; 6th South African Armoured Division & 1st Brazilian Division. In February, the US 10th Mountain Division arrived and participated in some raids during the winter. Just prior to the April Offensive, the Canadian Division was pulled out of Italy and sent to France/Germany (even though this is not what happens in "The English Patient").
Here is a graph I made to show the pull out of US troops in July/August 1944.
Steve
In 2 months, 9 complete division and the equivalent of 1 more were reassigned.
Source: Operations in Sicily and Italy - West Point Academy, 1947