There are quite a few Juniper ones[0], though they take the format of a tutorial rather than a discursive/magazine format though, which is OK, but not what I want when driving.
There's a tool called 'Handbrake' for the Mac which can be used to re-encode the nanog (and other meeting) video downloads to a format suitable for the iPhone/iPod/iPad. This is quite good for flights/trains.
Andy
[0] Example = http://itunes.apple.com/podcast/junos-as-a-switching-language/id292449024, some others are linked from the bottom of this page,