Rear-End Clicking..

Lately I've noticed a mild amount of binding through turns under power, but I figured "hey, it's a 10 year old Subaru.. what're ya gonna do?" But now there's THIS.. When I make a right-hand turn any sharper than about 70 degrees from a complete stop, I get a faint clicking noise from the right-rear of the car. It only happens when I'm powering through the turn--if i just glide through under momentum, there's no problem save for a tiny amount of tire skip if I've got it near the adhesion limits, which I don't do very often.

I'd just assume right off the bat that I need to take a good long look at my rear differential and at least maybe change the fluid. Does anyone have any other input? I appreciate it..

-Adam