Instruction from the TextMate site, this is the minimal info for installing TextMate Bundles

mkdir -p /Library/Application\ Support/TextMate/Bundles cd /Library/Application\ Support/TextMate/Bundles svn co http://svn.textmate.org/trunk/Bundles/Haskell.tmbundle

Update all bundles cd /Library/Application\ Support/TextMate/Bundles svn up *.tmbundle