I used this guide to replace my hinges, but I noticed that the real problem was that the display was separating from the case. I Googled it and found a few reports like (https://discussions.apple.com/thread/371...) indicating that Apple has a replacement program in place addressing this as a latent defect.

I took my machine to the local Apple store, and even though I bought it at the end of 2008, they replaced the display for free.

If you're having a display separation issue it's worth seeing what Apple says before digging into it.