For 1.9 Woool client you will need Hex Editor (Ultra Edit) and for interface work you will need the SGL Editor which is posted somewhere in woool section.
For 2.0 Woool all you need is a Hex Editor as everything including the interface is now hard coded strings.
To answer your PM's, no one works on woool, and yes i no longer work on woool 1, i did start on woool 2 but it's too much work which i cba doing.