If this article has made you more curious about Awk itself, I highly recommend The Awk Programming Language [1] by Aho, Kernighan and Weinberger. It's a terrific book all around (look at the list of authors), and Awk really is worth knowing if you use the command line a lot. (Credit where it's due: silentbicycle always recommends this book, and I read it on his advice. But I seem to have beaten him to this thread.)
[1] http://cm.bell-labs.com/cm/cs/awkbook (This link seems dead at the moment. I'm very much going to hope that's temporary.)