Don't like WWDC's website? Use this app to watch WWDC sessions on your Mac.
To download the latest release, click here.
You can perform an advanced search using the qualifiers "year", "focus" and "track".
Example searches:
year:2013 focus:ios scroll
year:2014 track:frameworks cocoa
track:frameworks core
WWDC for OS X is integrated with ASCIIWWDC, so you can see and search through transcripts of the sessions while watching the videos.