Correspondences - News By the People For People: Who captured Saddam Hussein?: "Well, the cat is out of the bag so to speak. Saddam Hussein was captured by Kurds, not US forces. Here is the story as best I can determine by looking through a number of articles (see full list at end of this post).
Hussein was betrayed to the Kurds by a member of the al-Jabour tribe because Hussein's son Uday had raped a daughter of the tribe. Saddam had previously paid 7 million pounds in blood money to the tribe with the warning that he would wipe out the entire tribe if it ever came out. (Sify report)
He was then handed over to the Kurdish Patriotic Front who negotiated a deal with US forces for political power before drugging and abandoning Hussein for pickup. Ultimately he ended up in the hands of the Patriotic Union of Kurdistan (PUK) led by Jalal Talabani (Aljazeera)
Hussein could not escape the hole in which he was recovered because the entrance had been sealed."