Hm, it looks like there was a samples/simple-cms project in the grails distribution as late as grails 0.5.6 - after that, all samples were apparently removed. The latest development code in
http://svn.codehaus.org/grails does now have a grails-samples directory, but simple-cms is not one of the projects there. Perhaps changes in grails itself broke the earlier examples, and they removed the samples until such time as people had an opportunity to update them. Just a guess. The grails-user mailing list archive has various people asking where simple-cms is located, and also some people saying they can't get it to work. So far I haven't found a clear statement of what happened. It might be worthwhile to simply ask yourself.
Ah, after some more digging:
http://jira.codehaus.org/browse/GRAILS-1115 The book
The Definitive Guide to Grails has some sample login code in chaper 7. I've seen some comments to the effect that this book is now out of date, and a second edition is planned. Dunno how applicable that is to their login code.
I'm guessing the best bets right now are to look at the plugins for
Acegi or
JSecurity. I can't say anything about them myself really; I've just browsed very briefly.
[ February 26, 2008: Message edited by: Jim Yingst ]