Cookware by brand
Le Creuset
Le Creuset pans are made of cast iron and can be used on induction cooktops. Many comments on the web attest to this and suggest that Le Creuset works very well on induction cooktops. Manufacturers website
All Clad
According to All Clad, all of their stainless steel cookware is suitable for use on induction cooktops with a few exceptions that they are not able to manufacture using 18/0 stainless steel, and are not induction compatible. Manufacturers website
Calphalon
To quote from their email response of June 2008, "...currently the only cookware we manufacture that is induction compatible is our Enamel Cast iron and our pre-seasoned cast iron. Our hard anodized, infused anodized, and stainless steel products are nonmagnetic, therefore not compatible."Manufacturers website
As soon as I have a few more answers from manufacturers, I will post a summary here