What is the preferred way to report bugs?

I've just stumbled upon two:

1. when mouse cursor approaches top edge of the screen, preview stretches vertically so that it's still square, but pixels are twice as tall as they are thick. That's on an mbp5,5 running 10.7.1.

2. Cmd+Shift+p uses physical location of p key disregarding programmatically set keyboard layout. I've only noticed because I'm using Colemak.