Check out this link for a concise summary of the indisputable evidence:
http://www.thenation.com/doc.mhtml?i=20050620&c=5&s=bergen
In fact, according to a widely reported background briefing by Pentagon officials in mid-December 2001, there was "reasonable certainty" that bin Laden was at Tora Bora, a judgment based on intercepted radio transmissions. Last year, Luftullah Mashal, a senior official in Afghanistan's Interior Ministry, told me that based on conversations he had had with a Saudi Al Qaeda financier and bin Laden's cook, both of whom were at the battle, bin Laden was indeed at Tora Bora. In June 2003 I met with several US counterterrorism officials, one of whom explained, "We are confident that [bin Laden] was at Tora Bora and disappeared with a small group." And the editor of Al-Quds al-Arabi newspaper, Abdel Bari Atwan, a consistently accurate source of information about Al Qaeda, has reported that bin Laden was wounded in the shoulder at Tora Bora. Indeed, in an audiotape released on Al Jazeera television two years ago, bin Laden recounted his own vivid memories of the Tora Bora battle. "We were about 300 holy warriors. We dug 100 trenches over an area of one square mile, so as to avoid the huge human losses from the [American] bombardment." And last August Al Sharq Al Awsat newspaper published the account of a Moroccan guard of bin Laden's, Abdallah Tabarak, who was also at Tora Bora: "We entered Tora Bora, where we stayed for twenty days. From there, Ayman al-Zawahiri fled.... Afterward, bin Laden fled with his son Muhammad." In short, there is plenty of evidence that bin Laden and hundreds of his followers were at Tora Bora, a fact that undercuts both the Bush Administration's and Curtis's reconstruction of the battle.