I'm seriously considering going to this colloquium today :
Clifford M. Will (McDonnell Center for the Space Sciences,
Washington University, St. Louis, USA)
Title: "The Confrontation between General Relativity and Experiment"
Abstract : " We review the experimental evidence for Einstein's general relativity. Tests of the Einstein Equivalence Principle support the postulates of curved spacetime, while solar-system experiments strongly confirm weak-field general relativity. We describe the status of the recently concluded Gravity Probe B gyroscope experiment. Binary pulsars provide tests of gravitational-wave damping and of strong-field general relativity. Recently operational laser interferometric gravitational-wave observatories, and a future space interferometer, may provide new tests via the properties of gravitational waves."
I've often wondered what Gravity Probe B will tell us about gravitation. If you want an introduction to the experiment, you can find it at Stanford's site at http://einstein.stanford.edu/
If I actually get there, I'll let you know how it went.
UPDATE : The talk was very good, an rather interesting too. Appartently the gravitational community has been comparing general relativity with experiment since the 60's, and has been ruling out many alternate theories as a consequence. A very good review can been found here.
In addition, the gravity probe B results will be unveiled mid january. The speaker is part of a NASA advisory board, so he already has an idea, but as he put it "if I tell you now, I'd have to kill you".