If it's hydraulic power steering, there's a couple of things you want to check first, before you go to replace the CV shafts.
Firstly, it may seem simple but check the fluid level. Bleed the system by turning the wheel fully to both sides and returning to the center, then make sure you have plenty of fluid.
If the noise is a more of a screech, check the serpentine belt running the power steering pump for slack or slippage, replace if necessary.
The pump itself is probably fine if you're only hearing the noise while turning sharply.
If none of the above is an issue, the CV joints are indeed the culprit.
Side note @incarnation: That is a very interesting looking car in your profile picture! What is it?