Bishops Problem

Puzzles and mathematical problems on the chessboard keep me going when playing gets dull or Im in a slump. Their are a bunch of them on http://mathworld.wolfram.com/ that I will be posting on over the next week or so. I am by no means a mathematician so I will leave out some of the more complicated equations that I dont understand and you probably dont either. Their is a similiar post about an original knight problem at http://knightskewer.blogspot.com/2006/09/guarinis-problem.html . Try them out, often their is more than one solution.

Find the maximum number of bishops that can be placed on an nxn chessboard such that no two attack each other.

Find the minimum number of bishops needed to occupy or attack all squares on an nxn chessboard.