Linux Tutorial and security in Linux

Here is a list of Tutorials about Linux and some of them about security in linux.
I Hope that you like them, and if anyone needs me to make a tutorial for something particular please dont hesitate to ask.

1- Installing Ubuntu Using VirtualMachine
( http://www.youtube.com/watch?v=ZdTfWWYA-bc )

2- Introducing Ubuntu 11.10
( http://www.youtube.com/watch?v=HT8pcBl1EIk )

3- Compiz in both Ubuntu 11.10 & 10.10
( http://www.youtube.com/watch?v=LwTqzPbuf7k )
( http://www.youtube.com/watch?v=KQcwmRmH9-k )

4- Blocking Ports in Linux using IP Tables
( http://www.youtube.com/watch?v=1hq1EuRlqX0 )

5- Basic/Simpe Howto Installing Application using Both Ubuntu Software Center and the Terminal ( Beginner guide )
( http://www.youtube.com/watch?v=-nlbKIn_0HY )

6- Using CHKROOTKIT and RKHUNTER to detect Rootkits ( Basic Overview )
(http://www.youtube.com/watch?v=ydL847SrMWE)