As a CU employee - creating a MySpace/Facebook page for the CU is a great idea. Over 70% of 15 to 34 year olds are using MySpace/Facebook. Why not go for the target market where they spend the majority of their time. MySpace is the most trafficked website in the US. Keep it current, not sales-pitchy, and relevant to the age demographic and it could do wonders for your deposit and loan growth. Have someone on your staff who's using the sites (and young enough) to develop it for you. You'd be amazed at what the non IT staff folks can do with a page layout and graphics these days.
As a MySpace/Facebook user - there is no way I would friend my financial institution on a social networking site. Seriously... that's like asking for ID theft. Let's see, myspace gives your age, location and now I know where you bank. It doesn't take much to look through a few photos and friend comments, read your blog, use a little zaba search and any decent hacker will have your ssn and all sorts of information to crack your account in well under 24 hours. I might take a look if I saw a great rate displayed on the screen, but even then, the ad-viruses that are rampant on that website are so well known for wreaking havoc that if you're smart you won't click on it no matter how safe it looks.
So in the end... it's still good for CU's to get the free marketing. Plus the average MySpace/Facebook user isn't going to be as smart as those of us who work in a financial institution and see the effects of ID theft on a daily basis so your CU might get a few thousand friends if you're lucky... Actually your CU profile will probably be invited out for drinks and a few other encounters as well. And offered a few ringtones, and get invited to play mafia, etc...