Turkey is under pressure from the US and NATO to enter the fray, but has resisted so far, only stationing some tanks and troops on their border with Syria. They have, until recently refused to even allow any Kurdish fighters to cross into Syria to help with the fight in Kobane. The Turks are caught in a difficult situation. They have fought a 30 year-old insurgency with Turkish Kurds ( there has been a cease fire), and so feel that any help for the Syrian Kurds ( the Kurdish nation is split among Syria, Iraq and Turkey), may result in a stronger Kurdish claim for their own country. Turkey has made some demands. They want the US and NATO to train the Free Syrian fighters ; they want the removal of Bashar Asaad and they want a "no-fly zone" so Syria cannot bomb the rebels fighting to topple Asaad. They are also concerned with the Iranian support for Asaad ( so is Saudi Arabia and other Sunna states).
The Islamic state has seized much territory in Iraq and Syria and are proving to be a formidable force, attracting recruits from all over, especially of concern are those from Europe and North America.
The Obama administration is opposed to sending any foot-soldiers. They will instead train forces from the region to battle ISIL on the ground. That will take time and ISIL has changed its tactics, resorting to quick attacks by small forces (which are less of a target for the US planes). ISIL is very well armed, with weapons captured from fleeing Iraqi troops and using "oil money' to buy more.
The indomitable Kurds of Syria and Iraq are fighting valiantly but they need better arms and more reinforcements. It's a stalemate, but two things can change this.... more and better weapons and reinforcements for the Kurds and the entry of Turkey. Also it has to recognized that Asaad is not going to go away and that with Iran's support, and with the recruiting of the Iraqi Sunni tribes (they had been badly treated by the outgoing Maliki Shia govt. in Iraq), ISIL can be severely weakened and eventually defeated.