A few years ago I bought two lengths of pipe insulation from Bunnings, about a metre long and was pre-cut down it's length. Easy to put on your bars, wrap with tape and you're set. Not sure if they still do it now though.
I'm sure you'd be able to buy rack pads from surf shops etc but if you want to keep it simple and cheap then DIY..
A great idea IMO was this (link below) that DJ posted back in May, the good thing is that you can take them off when you don't have the board on the roof. It's on my 'to do' list
www.seabreeze.com.au/Forums/topic.asp?TOPIC_ID=38294&whichpage=-1
