This is an excellent set of lectures about the Sunnah by Sh. Navaid Aziz.
The first video talks about the struggles of the predecessors in preserving the Sunnah.
The second video talks about the status and authority of the Sunnah.
The third video examines and refutes some of the alleged proofs used by those who reject the Sunnah.
The fourth video goes into detail about the preservation of the Sunnah.
The fifth video goes on to define some basic hadeeth terminology as used in the sciences of hadeeth.