http://www.washingtonpost.com/world/middle_east/in-syria-group-suspected-of-al-qaeda-links-gaining-prominence-in-war-to-topple-assad/2012/08/19/c7cffd66-ea22-11e1-9ddc-340d5efb1e9c_story.html

ALEPPO, Syria — A shadowy jihadist organization that first surfaced on the Internet to assert responsibility for suicide bombings in Aleppo and Damascus has stepped out of the shadows and onto the front lines of the war for Syria’s cities.
Here in Aleppo, the al-Nusra Front for the Protection of the People of the Levant, widely known as the Jabhat al-Nusra, is fielding scores of fighters, some of them foreigners, in the battle for control of Syria’s commercial capital, a key prize in the bitter war of attrition being waged across the country.

http://www.examiner.com/article/obama-s-war-syria

While Assad has been brutal in fighting the rebellion, actually most of the atrocities in Syria are being committed by the so-called rebels, many of whom are foreigner mercenaries. As reported in the Washington Post, even "groups suspected of al-Qaeda links [are] gaining prominence in war to topple Assad." In fact, Director of National Intelligence James Clapper testifies before the Senate Armed Services Committee that
"Al-Qaeda's branch in Iraq likely carried out recent suicide bombings in Syria and has infiltrated opposition forces fighting President Bashar al-Assad's regime."

The earlier paper provided references that more than $500M was initially provided by Saudi Arabia and the Gulf States (mainly Qatar) to a previous vice president of Syria to engineer the overthrow of President Assad.
There is now further evidence that Turkey is providing military training to Syrian rebels. One rebel fighter said, "The Turkish people are really helping us. Lots of people are getting training in those camps."
The Telegraph interviewed two journalists who were kidnapped and released later by the Syrian rebels. They indicated that "British citizens are among Islamist fighters and the camp members reportedly included people from Pakistan, Bangladesh and Chechnya, with no Syrians present."
As reported in Reuters, "President Barack Obama