There is a Creative Commons filter option that will limit your search results to videos with stated licenses. Check out the other helpful filter options as well (date, length, etc).
To see the license for a YouTube Video, click on the Show More option on the About tab. The section will expand the the license should be located near the bottom. If it is a Creative Commons license, it will be a hyperlink that you can click for more information.
There is an option to limit search results to only show items with Creative Commons licenses. On the main search results page, look for the Advanced Filters option on the right. This expands into a menu of filter options, including date uploaded and length. At the bottom of this menu, you will see a drop-down option for license. You must select a particular Creative Commons license; it will not search all CC videos at once.
Vimeo videos show license information directly under the video, next to the title and creator name. You can click on the icons to see the full license from the Creative Commons website.
Creator LastName, FirstName. "Title of Video." Name of Site. Version number. Name of publisher, Date posted. Web. Date of access.
For citing online videos, see section 5.6.2.d of the seventh edition of the MLA Handbook for Writers of Research Papers.
VIDEO BLOG POST
Creator, A. A. [Screen name]. (Date of Upload). Title of video [Video file]. Retrieved from http://website.url
Davies-Carr, Howard. [HDCYT]. (2007, May 22). Charlie bit my finger - again! [Video file]. Retrieved from https://www.youtube.com/watch?v=_OBlgSz8sSM
The Tonight Show Starring Jimmy Fallon. (2014, June 17). Jimmy and Kevin Hart ride a roller coaster [Video file]. Retrieved from https://www.youtube.com/watch?v=OPdbdjctx2I
JasonHawkes. (2013, June 13). New York aerial footage [Video file]. Retreived from http://vimeo.com/68384616
View the Reference Examples section 7.11 of the sixth edition of the Publication Manual of the American Psychological Association for more information.