The Olympus E520...along with all the rest of the E-series bodies except the new, professional E5 that sells for $1699.00...has been discontinued. It is possible that the E5...being a new model...is still in its initial manufacturing run and will itself be discontinued when the run is exhausted.
The E-series has apparently been replaced by the PEN series, an amalgam of a point-and-shoot and a traditional DSLR. It woul appear that Olympus has all but abandoned the manufacture of consumer-grade and pro-sumer DSLR camera bodies...and may possibly discontinue them altogether.