Code, code, and then code some more.

I've read quite a few similar posts over the last few months and that has been the answer almost every time. Can't say I disagree.

Going back to school will take years, cost you some good chunk of change, and when you're finished you'll likely look back and realize all the programming you learned was in your spare time anyway, not due to class.

Pick a language/framework, a project, and start learning.

What kind of engineer are you? You mention having foundations in C and Matlab; is this something that you would be interested in building on or do you want to leave the engineering world completely? I spent a lot of time hanging around the Image Processing / Computer Vision lab during university and pretty much everything they did was in Matlab and C / C++ (ImageMagick and OpenCV).

Just as an alternative viewpoint, I worked at a DOE national laboratory on a big image processing system for the USAF, and we used C++, Python, and the PIL. Believe it or not PIL is really fast, in fact I tried to optimize the C and couldn't do much with it, really. (Of course that probably says more about me than anything!)

Just saying that Python has massive inroads in scientific computing, so you can't go wrong learning it for that purpose. Just make sure you keep your eye on C/C++ as well, as you will need it to do your mathematical algorithms - Python libraries are fast because they are coded in C, so if you do anything computationally heavy that can't be offloaded to a library, it should also be in C.

You don't need a compsci degree to do web development. Learn python and pickup http://www.djangoproject.com/. Sure there are many alternatives, but beginners often are overwhelmed with choice. Take those two and go build!

Im not that good at just reading about a language or going through tutorials. I typically have to have a target project to keep me focused and use that to learn new languages. Decide what you want to build and start building it.

Sounds like you may be in a good position to do a startup that makes life easier for people in your profession. There's always need for good designers, too. Give your skills a go in the freelance world and see what happens.

Can you make your existing job more hacker-y? Can you work your passion as a hobby, for a non-prof etc?

If your dream is to be involved in a web app startup, polish your skills, start small and start one.

Don't quit your job because of that though.

I asked a similar question recently and the best answer I received was to start coding on the side, then once your side project can bring in an income that matches what you make now, you can pursue it full time.

If you already have an engineering degree and you are numerate, then pick up Knuth and start reading. After that, Abelson/Sussman.

It is advisable that you do this before picking up "Learn Ruby/Erlang/Clojure/node.js In 13 Seconds" or whatever the latest shiny toy is that the startup groupie kids are fapping to this month.

Between Knuth and Abelson you will have a solid foundation that 90% of web app hackers lack, and will likely be capable of becoming good with whatever tool you choose to use.