15 homemade Swiffer cloth patterns includes patterns for knitting, crocheting, sewing and even a no-sew option for the craft challenged (it uses an old sock... brilliant!)
It also includes a link to a pattern to make your own Swiffer duster and how to take the cap off of a Swiffer wet-jet canister so you can fill it with whatever cleaner you prefer.
The link to the full article in tipnut is HERE.
I personally saw a reusable Swiffer style cloth at Dollarama an just picked one up the other day and then use a spray bottle to get the floor a little damp with a home made cleaner. I'm not as fancy as some people with the whole "Swiffer system" but it works for me.