The cs50 lectures stated in January 2015. Where can I access the videos? YouTube and iTunes U only have the 2014 edition.
The current versions (Fall 2015) of the lecture videos are available on youtube at the following link: https://www.youtube.com/playlist?list=PLhQjrBD2T383Xfn0zECHrOTpfOSlptPAB However I don't know if those match the pset(s), etc. of what's currently available on the edX CS50 site.
If you enroll to this course here, you should be able to click the "Courseware" tab where you'll see all the video material.