Again, via the NY Times Lede blog (which has been a terrific source of information):
"The BBC has posted newly uploaded amateur video from Saturday’s protests that appears to show protesters clashing with security forces on motorbikes. As with other videos, the BBC could not verify the exact location or time the video was taken."
http://thelede.blogs.nytimes.com/2009/06/21/sunday-updates-on-irans-disputed-election/