The overmat and backboard should be attached to each other using acid-free linen tape or Filmoplast tape hinges. Overlay and floating mats are the two most common window mats. In floating mats, all of the print's paper is showing. For many years woodframes have been the frame of choice for fine art. The frame you choose should complement, not overpower the print.
Most people pick a simply stained wood frame.
If you'd like to be more creative, try exotic wood frames or use double overmats. These prints should always be covered with glass or Plexiglas. In either case, the print surface should not touch the glass when framed. Plexiglas has the safety advantage of being unbreakable, but it scratches easily and may attract dust. A special Plexiglas cleaner is available to help reduce static electricity problems.