free WebDAV client (and SkyDrive tool) under Windows

Rei's Shed - WebDAV Client CarotDAV - (support MSN SkyDrive)
http://rei.to/carotdav_en.html

FTP, SFTP and WebDAV client
http://www.bitkinex.com/

SkyDrive Simple Viewer for WebDAV
http://skydrivesimpleviewer.codeplex.com/