These instructions are now outdated. See http://charliesquires.wordpress.com/2009/10/02/installing-groovy-and-grails-bundles-in-textmate-updated/ for updated instructions. Thanks!
The Groovy website’s instructions for installing the TextMate bundle are very vague. They point you to the bundle location and link you to the TextMate bundle instructions (which are useful, but long when all you want to know is how to install bundles). Here’s all you need to do to install the Groovy and Grails bundles.
Open Terminal and run these commands:
mkdir -p /Library/Application\ Support/TextMate/Bundles
cd /Library/Application\ Support/TextMate/Bundles/
svn co http://svn.textmate.org/trunk/Bundles/Groovy.tmbundle
svn co http://svn.textmate.org/trunk/Bundles/Groovy%20Grails.tmbundle
Thanks it is short and sweet.