"Entry-level" job descriptions that require 2-4 years experience don't actually require 2-4 years experience. They require no experience but the gumption and savvy to recognize that what the employer's actually testing for is your ability to read between the lines in what they ask, learn what they value, develop skills quickly, and market yourself well enough to convince him you have those skills.

Pretty much everyone in the field knows that you can train an enthusiastic and reasonably intelligent newbie up to a useful junior dev in about 2 months. What they don't know is whether you're an enthusiastic and reasonably intelligent newbie. The skills I mention above - reading your boss's mind, learning things you don't know, and convincing people to take a chance - are far more important than any technical skills you can learn.

I guess that is probably the easiest route, but definitely not the only one.

Work on a couple of projects, alone or with friends. Learn new stuff on your own. Be confident. From my experience this works like a charm.