Hiya Frank212.
There is another topic that I started called "iDisk access from windows" that discusses this very issue (and a potential security risk with this type of access).
BTW, to log in from windows you cannot simply type the address you listed in the address window in IE. You MUST go to File\Open and type the address there. Below it is a checkbox that reads "Open as web folder" which you must check on in order to make IE connect through the WebDAV protocol (which is what allows you to connect to your iDisk from Windows). You will then be prompted for your mac.com userid and password.
Happy filesharing !!