I would like to make a box with a fixed width and height, like the ones in the right margin of Apple's webstore located here:


How do I do that?

Also, is there a way to make said box "stuck" to the upper-right hand corner of the user's screen?

This box will be used for special announcements and advertising, so it should always appear on the user's monitor even if the page is super tall and they scroll all the way to the bottom.

Hope that makes sense?!