all the inches lose me (i'm decimal)
Photoshop is for editing images - if you artwork is just an image.. 300dpi is fine for it too appear at it's best in print
but keep in mind that lineart (text and graphics) are printed at around 1100dpi on a litho press.
illustrator/freehand or quark/indesign are the programs to use for page layout and printwork involving lineart.
photoshop is an unrivalled image editing program but it's a case of horses for courses when it comes to print.