1. Labminutes

This is one of the most interesting YouTube channels I know. If you work with Cisco technology and want to gain some practical knowledge, the labminutes channel is for you. In this channel you will find video lessons divided into 3 categories: Wireless (1 video) Routing and Switching (27 videos), Security (63 videos). If you want to learn more about instalation of Nexus 1000V, Cisco ISA, DMVPNs or IPSEC tunnels, this channel is for you.

2. Keith Barker

Keith Barker is one of the most skillful and funny instrucotrs on the planet. Today he works with CBTNuggets, but still creates short videos on YouTube about different technologies, mainly security, IPv6 and networking. Highly recommended.

3. CBTNuggets

CBTNuggets is a company I trully love. Keith Barker, Jeremy Cioara and several other amazing instructors. Their YouTube channels is updated weekly. You will find here videos about networking, Backtrack, certifications, virtualization, Microsoft Windows, etc.

4. INE Training

This channel is dedicated to network engineers who think about becoming an expert (CCIE). INE few times a month uploads a new video from their list of great trainings.

5. TrainSignal

TrainSignal is also a training company. TrainSignals uses YouTube to promote their training and gives a lot of value uploading new videos few times a week. You will find here short video trainings about networking, system management, virtualization, etc.

[Extra] 6. Eli the Computer Guy (thanks Rahul)

This one was recommended by Rahul. Eli has amazing talent for sharing his knowledge. You can find here a lot of great video trainings about computers, servers, networking and more, more and more.

[Extra] 7. Chris Bryant (thanks Bart Van Den Bremt)

Another great channel recommended by Bart Van Den Bremt. This channel is targeted mainly to Cisco engineers (CCNA, CCNP level). Updated regulary with nice labs.

[Extra] 8. Kevin Wallace (thanks Luis Mediavilla)

It is another great channel for Cisco engineers. Kevin Wallace is CCIE RS/Voice and has amazing teaching experience.