First, the UVC drivers. To install them, you need to connect to your Yun via SSH. Simply open a terminal, and type:
opkg update
opkg install kmod-video-uvc
opkg install python-openssl
opkg install fswebcam
opkg install mjpg-streamer
cd /mnt/sda1
fswebcam test.png
--- Opening /dev/video0... Trying source module v4l2... /dev/video0 opened.