Another nice location is linuxcommand.org for shell scripting things. Like said, knowing shell scripting isn't necessary for a Linux user, and learning shell scripting doesn't necessarily mean you need to be a Linux user. That's because the shells for which you create scripts (note that depending on the script contents, it might or might not work with all shells) aren't Linux-only: if you know how to write scripts for Linux, you know the basics of how to write them on other platforms as well (like Unix, or Windows -- it's common to use "scripts" or batch files in the latter one too). Knowing how Linux works helps getting the result done (in the script), and on the other hand knowing how to script may ease the use of Linux in some cases (depends a lot what you're doing). But I don't think either one depends on the other one more than just a little.
In my opinion it's healthy for anyone to know the basics of shell scripting, or whatever it is called in the environment in question. Graphical interfaces may make life easy, but often they just can't do what scripts can - automate, batch-process, ease up and easily modify a task that has several steps.