making "piddle pads"

I would like to make some organic "piddle pads" for our coming baby, but am not quite sure how to approach this. I have seen them sold online as (a) wool (very expensive!); (b) plastic (not an option!); or (c) fleece/terrycloth. I'd like to use them as mattress protectors as well as changing pads, etc.

I have some nice, natural wool batting - but I'm not sure how to create a washable pad from this? Would a couple of layers of felted wool - like what is used in diaper covers - be a better idea? If so, what are the best mailorder sources?

If I went with hemp/cotton fleece, terrycloth, etc., it would be very easy for me to find organic mailorder sources for these fabrics ... but how many layers would you suggest?

Thanks in adviance!
Pam
edd 9/28/2003