To actually give a bit of advice, it matters as to whether we're talking about an Aluminum (Aluminium) Cinema Display, or the old Plastic ones. The plastic ones aren't actually that difficult to get into, except for a bit of glue here and there. The aluminum ones are intended to be a little tricky.
Certainly, if you take it to an Apple Authorized Service Provider, the job will get done properly. If you insist on doing it yourself, try and get a copy of the Apple Service Manual. The PDFs for these aren't all that hard to track down, especially considering that they're not "confidential documents" per se. Apple restricts who can download them from the site, but doesn't restrict passing them on.