I was thinking about this myself recently. I have not done it yet but I think a good way is to purchase a roll of adheasive magnetic tape. You can stick that to the wall, then put on paper, then put other long strips of the magnetic tape or small neodymium magnets over it to hold it up.

easier, faster, and less messy than plain masking tape, and no need to nail long metal strips onto the wall. various vendors sell this tape, and its pretty cheap with various lengths available.