The BBC: “What will happen to POWs?”:
“The United States has already opened one so-called Theatre Internment Facility designed to house 4,000 prisoners at an undisclosed location in southern Iraq.
The site is expected to expand to accommodate a further 4,000 prisoners next week.”

College journalist “embedded” in Southern Iraq:
“The 36th is involved in two main projects and a number of smaller ones. Perhaps the most important is the construction of the prison camps (called Ifs – Internment Facilities – by the army) at Um Qasr. … Two camps are under construction, another two planned, and four more possible, said Maj. Karen Ward, the executive officer of the 46th Engineer Battalion. Each camp is designed to hold 8,000 prisoners but could hold an additional 2,000 to 4,000 if necessary, she said. The plan is to eventually hold all Iraqi prisoners at Um Qasr.”

Also, from the tone of the second article – posted just two days ago – it sounds like the U.S. military is preparing for a long stay in Iraq.