I am learning this myself.
There are two things to take note: Mounting and Matting.
Mounting is putting a photograph onto a board. Matting is putting another board with a cut out "hole" for the photograph - the "window mat". Matting avoid the print touching the glass, apart from being more esthetically pleasing.
As far as choice of boards are concerned, "museum/archival/ragboard" quality is best. But the question I ask myself, do I really want such quality, when my pictures are not of such standard (yet!).
How "flat" do I want my photographs to be while on the mount? If you want the "best/flattest" mounting, then I think you need a press. This, depending on the size of the prints, will easily cost a few grand, together with the paraphernalia.
For the moment, I am contented to just mount my photos on simple board. I buy them from a shop in Bras Basah Complex, and cut them to sizes. For anything smaller than a 8X10 prints, the mount board is 11x14 inches. For my 11x14 prints, I use a 16x20 mount board. Because of the paper I use, my prints are reasonably flat. So I am not investing in a press (yet!). Just heavy books seem to do fine. I spray the back of the photo with 3M spray glue and then stick the prints onto the mount.
Looks OK to me!
There is a gathering this Sunday (2 January 2005) at EPsite at level 3 in Borders at 1-3.30 pm. (look under the subforum "Gatherings - black & white enthusiast) This is organised by jcryan and sponsored by Epson. I will bring a couple of mounted prints. (not matted). You are welcome to take a look if this is what you want/need.