Deal Extreme - 4 Retractable Metal DS Stylus - $2.42 & Free Shipping
Saw these on Deal Extreme, they apparently suit larger hands. Look good to me compaired to the fiddly pastic ones from Nintendo.
They still fit into the DS perfectly, and are always handy to have lying around incase you're like me and lose them!
Price is in $USD, but equates to around $2.67AUD