Yes, they used to be tied more to employer groups and now they are often open to anyone with membership in a low-cost group (such as PenFed) or anyone who lives, works or worships in a city or county where the CU has a presence.
The banks hate it. My CU is in California (I've been a member since 1988 when I lived there and when they were affiliated with strictly an employer group), but I keep much of my savings there because they always offer competitive rates. I believe the current rate is 1.3%.
"Hey, for every ten dollars, that's another hour that I have to be in the work place. That's an hour of my life. And my life is a very finite thing. I have only 'x' number of hours left before I'm dead. So how do I want to use these hours of my life? Do I want to use them just spending it on more crap and more stuff, or do I want to start getting a handle on it and using my life more intelligently?" -- Joe Dominguez (1938 - 1997)