I don't have a tutorial, but I can tell you that it is rather easy to do on almost any type of shape using gradients, and I use vector masks. It's not as gorgeous to look at, but it's really close and the time you save can be spent refining it. I'm going to assume you're fairly proficient with Photoshop.
My technique:
1. In this step, you'll be making the basic outline. I'd first draw the shape. You might want to use the free-form pen tool so you can have vector graphics. Then add a gradient overlay where the top is lighter than the bottom, but both colors are rather close to eachother. I'd make this step a medium shade, so you can add darker and lighter accents later.
2. In this step, you'll be making an outline for added depth. Make an outline of the above slightly bigger, and on a lower layer. Make the top darker than the darkest shade from the above "main" layer, and make the bottom a lot lighter than the top, but no lighter than the bottom of the "main" layer.
3. In this step, you'll be making the "glassifier," the thing that gives it it's glossy sheen. Here's the tricky part for me to explain, and it depends on the shape you used. I'll just assume you're trying to make a near copy of the apple logo. I'd use the free-form pen to draw the shape of the extra glossy area. I'd set the fill of the layer to completely transparent, and make a gradient overlay that went from an almost-completely-white blue to a blue that is just a few shades over the regular blue. Make sure you adjust the angle of the gradient to make it look its best. Then make it about 50 percent transparent. It depends on your taste, but I find it's often very close to there. Then you can do all of the above for the little apple leaf.
Sorry if this is kind of vague, I've only just discovered this technique, but it really does work well... I hope it helped even a little bit!
