Ibrahim Hassan Tala Asiri is a 29-year-old Saudi citizen, who is on the kingdom's most-wanted list. He is widely believe to be the individual responsible for the bombs used in the assassination attempt on Muhammad bin Nayyif, the one sewn into the underwear of Umar Faruq for his Christmas Day attempt, as well as those mailed to the US last week.
His younger brother, Abdullah, was the suicide bomber in the attack on Muhammad bin Nayyif.
According to this article from al-Sharq al-Awsat, he was born in the Saudi capital of Riyadh. The story of his childhood is picked up by Sada al-Malahim, in the "martyr biography" of his brother that appeared in issue 11. Ibrahim and Abdullah grew up in a very pious home, one that didn't approve of or watch "foolish tv sitcoms" or listen to music. Instead the boys of the family occupied themselves with memorizing the Qur'an. Their father, Hassan, was a soldier in the Saudi military.
This article from al-Hayat suggests that Ibrahim studied chemistry at King Saud University, but never completed his degree.
Both Ibrahim and Abdullah wanted to travel to Iraq to fight the US, but were involved in different cells attempting to smuggle themselves out of the kingdom. Ibrahim's cell was busted, and he was thrown into prison. After he was released he again formed a cell - this time Abdullah was in his cell - but it too was broken up. The Saudis killed a number of those involved, but Ibrahim escaped, and together with Abdullah left Riyadh on June 23, 2006.
The group made their way south, eventually reaching their family's home region of Asir. Here the biography gives an interesting inside story of what AQAP operatives from Saudi Arabia have to deal with in their attempts to cross into Yemen. (Also recommended: Robert Worth's recent article on the border.) Ibrahim recounts that they only had a small pistol and spent days dodging Saudi security patrols, before they finally crossed the border into Yemen on August 1, 2006.
Ibrahim Asiri goes by the kunya Abu Salih and seems to have spent some time talking with, if not studying under, Muhammad al-Rashad, a late Saudi member of AQAP, who fought in Iraq.