The graphic they put up leading in to the science update read "Opportunity Hits The Beach, Will Begin Momentarily"
Having said before that evidence was leading them to believe the rocks were weathered by water, They are taking it a step further.
Based on their best evidence and best minds the NASA scientists are saying that the rocks around the Opportunity rover were formed in water, possibly a shallow sea. The layering on some rocks indicate, upon close examination, that flowing or rippling water was the cause of the sedimentation.
They added that they plan to send the next Lander/rover that is scheduled to go to Mars, the Mars Science Laboratory to this same Meridiani Planum region to continue the research. It will be nuclear powered and will have sample return capability.
Pretty cool stuff. Also they didn't act nearly as nerdy as last time. Just a little nerdy.
Update: complete report from space.com