Yes. One of the best ways to acquire basic photoshop skills is to follow some photoshop tutorials.

There were numerous sites full of these on the web when I got started, and I'm sure there still are. Here's an example of what you're looking for:

http://psd.tutsplus.com/tutorials/tools-tips/use-over-40-adv...

Basically, it shows you how to create a concrete effect or object. The point is not to create the object itself, but to learn the techniques used to create the object so that when you want to create your own stuff, you have enough of a repertoire of techniques to achieve what you want.

As for places to get design critiques, I'm afraid I'm a bit stumped for that for them moment, since all the design communities that I belonged to back when I got started (around 1998) have died out since, but I would guess you can find them by starting with designer-oriented sites like smashing magazine or this psdtuts, and locating the forums attached to them.

Edit: I assume that you know where to learn CSS.

Thanks - I already know HTML and CSS, just don't know where to start with design.

Do this: go to delicious.com/popular/design. Find a site of which you love the design. Kick up photoshop, then push the pixels of the other site around till it looks like what you want. Find several sites and mix the elements. Pay attention to the fonts.

When you're done, get someone to convert it to HTML. Doing so yourself is a waste of your time.