I've had a couple of emails recently from people enquiring about how to get the source code for Grails plugins. Well, rather than write a whole set of instructions the good people over at grails.org have already done that for me.
The key bit is the instructions at the end of the page that tell you have to grab the source code for any plugin by navigating through the svn directory tree.
Have fun and, don't forget, all patches are most sincerely welcome!
