Photographic Solutions recommends their E2 sensor cleaning solution for the 1D Mark III and the 40D (most likely the 1Ds Mark III also) as they have Tin Oxide sensors.

I've been using the standard Eclipse solution with no ill effects, but I'll change now. No sense in taking any chances.

Here's a link to info on the new E2 solution

http://www.photosol.com/eclipse_e2product.htm