New observations suggests dark matter in hot water gas:

http://chandra.harvard.edu/photo/2007/a520/

Well, since I've always thought that 'dark matter' is nonexistent, I'm not surprised. I'll wait until the MOND theorists produce their own analysis of the cluster, with publication probably several months from now, but I will predict right now that the observed distributions and velocities of the galaxies and the hot gas will be shown to be right in line with MOND expectations.

Bill

Belgian and Chinese cosmologist link dark matter and the very first stars:
http://www.sciencemag.org/cgi/content/abstract/317/5844/1527

Rings and shells of "dark matter" as MOND artifacts

Mordehai Milgrom, Robert H. Sanders

MOND predicts that a mass, M, contained within its transition radius rt=sqrt(MG/a0), may exhibit a feature at about that radius in the form of a shell, or projected ring, in the deduced distribution of its phantom dark matter. This is despite the absence of any underlying feature in the true ("baryon") source distribution itself. The phenomenon is similar to the appearance of an event horizon and other unusual physics "in the middle of nothing" near the transition radius of General Relativity MG/c^2. We consider the possibility that this pure MOND phenomenon is in the basis of the recent finding of such a ring in the galaxy cluster Cl 0024+17 by Jee et al. (2007). We find that the parameters of the observed ring can be naturally explained in this way; this feature may therefore turn out to be a direct evidence for MOND. We study this phenomenon in simple, axisymmetric configurations aligned with the line of sight: spherical masses, a dumbbell of spherical masses, and an elongated, thin structure. The properties of the apparent ring: its radius, surface density, and contrast, depend on the form of the MOND interpolating function and on the exact three dimensional distribution of the sources (the thin-lens approximation is quite invalid in MOND). We also comment on the possible appearance of orphan features, marking the Newtonian-to-MOND transition, in high surface brightness galaxies. In particular, we find that previously unexplained structure in the rotation curves of some galaxies may be evidence for such features.

Observations of MACS J0025 supports findings of the Bullet Cluster, suggesting dark matter is collisionless:

http://hubblesite.org/news/2008/32/
http://chandra.harvard.edu/photo/2008/macs/

The paper linked from Hubblesite dismisses MOND as being unable to explain the strong lensing effects and only limited success with explaining the weak lensing.