This is a discussion that seems to have had more questions than answers — up until now.
Problem: You have a web page designed at 1,000 pixels wide, and just looked at it on a new iPad, and were nearly in tears over how badly your graphics and photos looked on there.
Solution: Photographer Duncan Davidson posted some very interesting findings, and I combined that with my own research and present the results at photojoseph.com/retina
(I also have a post specifically about loading images at an optimal resolution on the new iPad on ApertureExpert: Displaying Your Photography On The New iPad)