iPhone iOS how to create graphics effects like drop shadow, etc? What effects are built-into iOS?

I apologize for a large set of questions here. I'm starting to play with Quartz Graphics more and more, and found that it has interesting effects, yet I do not have many samples to see them in action.

 view.layer.shadowPath = [UIBezierPath bezierPathWithRect:view.bounds].CGPath;

There's a shadow property:

view.layer.shadowColor = [UIColor grayColor].CGColor;
view.layer.shadowOffset = CGSizeMake(5, 5);
view.layer.shadowPath = [UIBezierPath bezierPathWithRect:view.bounds].CGPath;
view.layer.shadowRadius = 9;

I was unable to make the shadow show though.

Borders:

 view.layer.borderWidth = 1;
   view.layer.borderColor=[[UIColor whiteColor] CGColor];

What other effects can I get from built-in iOS on iPhone? *Is there a comprehensive demo project that can showcase what kind of graphic manipulation functionality is built into iOS?*

How do I do transparency masking?

Is there a way to add inner shadow or inner glow? Is there a way to make an iOS button appear more "concave" than it really is?

Is there a way to do radial gradients? Is there a way to create multi-ray lens flare effects like Adobe Illustrator? Is there a way to blend layers using "lighten, dissolve", or other photoshop effects? Is there a way to dynamically adjust the brightness of the image? I know how to do hue shift.

I would appreciate any other hints on what kind of layer effects I can apply to the CALayers