Squyres et al. have a paper being published in the September 8, 2006, issue of Science:

Two Years at Meridiani Planum: Results from the Opportunity Rover
S. W. Squyres, A. H. Knoll, R. E. Arvidson, B. C. Clark, J. P. Grotzinger, B. L. Jolliff, S. M. McLennan, N. Tosca, J. F. Bell, III, W. M. Calvin, W. H. Farrand, T. D. Glotch, M. P. Golombek, K. E. Herkenhoff, J. R. Johnson, G. Klingelhöfer, H. Y. McSween, and A. S. Yen
Science 313, 1403-1407 (2006)
Abstract
Supporting Online Material

And since it's about Mars, it makes a good cover, too.

N.B. The "Abstract" and "Supporting Online Material" (SOM) links won't go active until later today, when the Science embargo is lifted.

I read it this morning. That was a great summary paper. I was particularly impressed with the way they tied a lot of detailed analyses and interpretations together into a neatly coherent summary of the significant discoveries made over the past two years. I had heard that the paper discussed the MI evidence from the target "Lemon Rind" for pseudomorphs of a cubic mineral in the form of hopper crystals, but I was disappointed that the MI mosaic in the pdf was of such poor quality that it was difficult to see what they were talking about. So I Autostitched a larger one.

I am not an expert on hopper crystals, but I always found them fascinating. There appear to be quite a few features in the image that look like cubic pseudomorphs, but I've pointed to what I think is the best example of what may be a hopper crystal form. These were briefly mentioned by Scott McLennon at the LPSC last Spring. I remember him showing a picture with three lines meeting at a common point with 120 degrees between them.
Click to view attachment

By the way, if anyone wants to see an example of hopper crystals of the cubic mineral halite, there is a good picture of some about halfway down on this page from the Detroit Salt Company.