Oxford Philosophy professor Peter Millican offers a nice response to William Lane Craig's cosmological argument for God. Below are some additional resources/videos on the Kalam argument.
A fairly detailed refutation of Kalam is available in this Countering the Kalam playlist.
Other good Youtube videos responding to Craig:
Oh, What a Tangled Web!
Matt Dillahuty has created a counter-apologetics wiki called Iron Chariots. You can find a detailed refutation of Kalam here.
And the full William Lane Craig vs. Peter Millican debate can be seen here.