What do I need in order to set up a 10 - 12 inch CCD telescope for a High School observatory?

This is a tall order. If I were going to set up such a facility my shopping list would include:

1. A top of the line, equatorially-mounted or yoke-mounted, telescope. MAny seem to favor Cassegrain-type instruments such as Celestrons. Newtonian reflectors have that annoying diffraction pattern due to the secondary mirror support which gives all stars a 4-pointed image. Cassegrains give a clean, round image.
2. The mounting needs to be a pedestal-type, fixed in concrete and properly oriented to the north celestial pole so you can take advantage of the clock drive and setting circles to find and track the stars for photographic work.
3. You need a good set of eyepieces, preferably Plossls or Naglers
4. Also, you should get a few optical filters to help improve your seeing and reduce some of the skyglow from city lights
5. You need a set of internal lights with a red filter so that you can read star charts and not ruin your night vision with standard indoor lighting.
6. You need to budget some money for supplying electrical power to your observatory for running the lights and the telescope. This will be a non- trivial expense over the lifetime of the observatory and you might consider putting aside some of your money in a bank account, and drawing on the annual interest for operating the telescope
7. You need a good set of books, star charts and atlases for finding objects.
8. You need to do some serious research to identify a good CCD camera. I recommend having a look at Sky Publishing Corporation's 'CCD' magazine to get some excellent suggestions. There are many good cameras in the $500 - $3,000 price range. They differ, principly, in the size of the array and their sensitivity.
9. You need to give some thought to where you are going to locate the observatory on school grounds. Of course you want it as far away from electrical lights as possible without compromising on safety
10. You might also consider buying a regular, 35mm film camera to supplement the CCD work. This will let students develop their own film and learn how various kinds of films work in conventional astrophotography.