Generally, you'll need at least 3 sharpening passes at varying times in your workflow - I wrote a little about it recently, so you might find
this here useful.
Photoshop is a VERY "deep" and "wide" program - you could do a 3 year university course on it, and still not master every feature & function. I suggest though - because it has such a profound effect of the outcome of our work - that one is well advised to invest in some training on it. Personally, I'd recommend popping along to
www.kelbytraining.com - signing up (only $24.95 a month) (USD) - and check out all of the online video material - it's really top-notch stuff (and no, I'm not on commission, darn it!).
Getting it right "in camera" is always best (wherever possible) - the last thing I want to do is have to more work on 1200+ images in Photoshop after a shoot than I really have to. But having said that, post-processing has ALWAYS been a part of photography (even in the film days). Personally I strive for getting stuff as good as possible in-camera, and then do whatever it takes to get the image looking it's best in Photoshop. Sometimes that's a little, sometimes it's a lot. You might as well face your fears and make it your friend though, because ultimately, there's just no way of avoiding it.