I am a web dev seeking deep knowledge of the Unix-style command line.
Please if anyone has a recommendation on any high quality courses avail. over the web respond to this thread.
If you're looking for a generic introduction to commonly-used tools (and how to pipe them together for awesome hackery), I highly recommend the Linux Phrasebook by Scott Granneman. It teaches individual useful commands and shows you how to build off of each to cover very common everyday tasks, making life easier. The book is 'pocket-sized' and only a couple hundred pages, but there's a lot of good info. Each topic/solution is at most a couple pages.
It is a book and not an online resource, but I personally have found it invaluable.
I agree with Bart, you should be a little more specific and select a distro. A good source for various online trainings in linux, be it beginner to expert is
I use VMWare to install different platforms and I agree that it is the best way, being hands-on, to learn.
TrainSignal.com has great training, although not free. I have used it for various Windows products while simultaneous working on a virtual machine.