I had a Late 2008 MacBook 13" (5,1) laptop and was saddened to realize that part of the keyboard was not working anymore. I wanted to get the laptop working again so I could give it to my son to use as his first computer.
I found this "Guide in Progress," "Upgrading your 2.0Ghz 13" Aluminum Unibody Macbook to a Backlit keyboard" and while incomplete it was sufficient to help me get the job done.
I found the part I needed on ebay for only $20, so even though the difficulty rating was "difficult" the instructions, while not complete, were clear enough that I thought I could replace the keyboard myself. That and the fact that iFixit made it really simple for me to get the tools I needed made this more like a little fun project than a chore.
There were a few pictures that didn't quite cover every step in the guide, but most of the lacking details were pretty obvious. The one bit of advice I would give is to be very careful not to strip any of the tiny screws that mount the logic board to the chassis. I stripped one myself and had to resort to risky methods to get around it. In the end I was able to compensate for my impatience but I would have rather spend a bit more focus and attention and avoided the whole mess.