for a preview..
According to dcresource :-
What's new on the E-520? Pretty much the same stuff that you'll find on the recently announced E-420. Those items include:
Larger, 2.7" LCD display (versus 2.5")
Contrast detect autofocus (with select lenses) and face detection with live view
Faster continuous shooting speeds (3.5 vs 3.0 fps)
New vertical and horizontal panning IS modes
Shadow Adjustment Technology brightens dark areas of your photos
Perfect Shot Preview lets you see the effects of exposure compensation and white balance settings on your subject before you take a photo
Wireless flash control
As you can see, the E-520 is more of an evolution of the E-510, rather than something radically different. Olympus has dropped the EVOLT moniker from their D-SLRs, as well.
to me the new IS mode is a good new feature..wireless flash control is also a plus point!