All the suspects deny links to terrorist groups
The calls were made from abroad by someone using the name Shakur, and were picked up by Spanish police.
"I am preparing certain things which should please you," Shakur said at the beginning of August.
"In our lessons, we entered the field of aviation and we cut the bird's throat," he said on 27 August, apparently speaking in code, in a call to one of the arrested men, Imad Eddin Barakat Yarbas.
'Extreme' security
The eight men have been charged by investigating judge Baltasar Garzon with offences including "a terrorist attack against people".
They are among 11 men with Tunisian, Algerian and Syrian backgrounds arrested last Tuesday in Madrid and the southern city of Granada.
Three have been freed, but will have to return to court when asked.
"The extreme security measures and the coded nature of the conversations indates that they were referring to 11 September," Mr Garzon said.
All 11 denied having any connection with any terrorist group or Bin Laden.
Hamburg connection
Garzon said Imad Eddin Barakat Yarbas's telephone number was found in the Hamburg flat of Mohammed Atta, who is believed to have been the hijackers' leader.
He said he thought a Spanish al-Qaeda cell had been formed in the mid-1990s, and recruited Islamic fighters for the conflicts in Bosnia, Chechnya and Afghanistan.
The eight men were also charged with belonging to a terrorist organisation, theft, falsifying documents, and illegal possession of arms.
Police seized computer material, videos of Islamic guerrilla activities, hunting rifles, swords, false identity documents and a substantial quantity of money in the raids.
Judge Garzon is best known internationally for his attempts to have former Chilean dictator General Augusto Pinochet extradited to Spain to face trial for human rights crimes.
Strasbourg
The arrests in Spain follow a number of arrests across Europe, as authorities move against those with suspected links to Bin Laden's group.
Last week, five Algerian militants alleged to have links with Bin Laden were arrested in Strasbourg.
The four men and one woman were said to have been plotting to launch attacks in the French city.
They were also suspected of organising the escape to Spain of Mohamed Besnakhria, an Algerian said to be one of Bin Laden's chief lieutenants in Europe.