Well, the wiki page I linked to has the full description, but in a nutshell:
"Free as in beer": No monetary cost.
"Free as in speech": You get the source code.
I can write software, and give it away for free, without giving out the source code. That is free as in beer.
I can write software, and give out the source code, but require a license fee for use. That is free as in speech.
I can write software, and give it away for free, and give out the source code. That is free as in beer, and free as in speech.
Most OSS projects fall into the last category, but obviously not all. The plethora of licenses is evidence that no one model fits all needs, and no one (well, no one outside the FSF) should really expect them to. Decide what works for you, and find a product with a complementary license to your situation and/or political stance. :)