I think that the best way to learn something is to experiment with it.. so the best way to learn linux is to install and try to use the hardest one distro - after installing redhat, and mandrake, I didn't know what was happening when I was using it, it was very similiar to Windblows - there was something goinon, but you didn't know what, if you pressed this and that.. So I installed debian, and after screwing it few times I finally was able to control what was happening at the moment..
One more thing.. Linux isn't so hard to learn..
I found it similiar to AmigaDOS and Workbench when I was using it for the first time..