The thing in Australia (and there is also a company in the US), is called "mattress wrapping". Basically, you wrap the mattress in a plastic bag to prevent fumes. (Also, if you use a mattress pad over the plastic wrap, then you supposedly aren't doing it properly unless your mattress pad/sheet/etc. is 100% organic cotton.)
All of the research that supports that this work comes from the companies selling it (unless maybe I've missed it), so I'm not sure how much I really buy into it. I did some googling about all of this supposed research and came up with nothing, though I did find this blog that tried to track down the source of some of this supposed research and you can see some of the glaring flaws: http://www.joannabk.com/babyblog/2006/10/sids_and_mattresswrapping.html
That being said, we did buy an "organic" mattress (no PVC, etc. but it's not 100% organic- they don't really enforce claims like that- because it has been treated with boric acid as a flame retardant).
I read somewhere that babies are 7x more likely to be stillborn than to die of SIDS, so while I'm definitely neurotic enough to take the risks of SIDS seriously, (and believe me, in addition to the stuff above we have 2 different types of movement/breathing detection monitors), I'm not buying into this special mattress business at this point. I haven't decided about if we will wrap it, apparently there are some links out there which tell you how to make your own wrap from the same material at Lowe's/Home Depot/ etc.
Me (29) DH (30)
#1-Olivia Caetlyn-9-28-09-9-28-09, 23+2 wks, emergency classic c-section, class I HELLP, IUGR
#2- Lucas Oliver (rainbow baby)- April 2011, 36+2 wks, HELLP and pre-e free! (lovenox and LDA pregnancy)
#3-Matthew, late October 2012...mostly normal, 37 wks, (lovenox and LDA again)
My blog: http://www.butterflies-and-rainbows.blogspot.com/