Bin Laden was killed Monday in a huge compound in Abbottabad, Pakistan, during a raid by U.S. Navy SEALs.
Some of the Web sites have been used by bin Laden's terror group to air its statements and transmit its leader's messages, CNN reported. They have also been used to attract jihadi recruits.
"Congratulations for dying as a martyr and a fighter in the sake of Allah," one message said.
"We won't cry today, but we will revenge. Men and women in America will cry," another said.
Another message called bin Laden "the Lion of Jihad (who) was killed in a fierce battle."
"May Allah give you a place next to our beloved Prophet (Saws or Peace be Upon Him) …," wrote another.