I put a larger hard drive in my MacBook. This is a pretty straightforward process and Apple thoughtfully provide a fully illustrated guide. However, there are a couple of gotchas:
- The drive sits inside a cradle, which is fastened to the drive using special star screws (not Torx). There are several special (often labelled "security" or "anti-vandal") screwdriver bit sets sold that may contain the appropriate bit. I happened to have one and their use seems to be increasing since I have a Seagate external drive that stubbornly refuses to be opened with anything except a special bit. You can always derive pleasure from opening pay phones, vending machines, etc. when you're done!
- To get MacOS on the new drive, you need to boot from the system DVD. Since the drive is unformatted, you need to format it using Disk Utility. When you get to the License Agreement in the MacOS installer, look at the menu bar and you'll see Utilities. From here you can start Disk Utility and should see your new drive identified. You want to give it a suitable volume name and Erase it. Note that in the build I was installing, there's some kind of screen repainting bug and you may need to drag the window around to see updates. Also, since everything is running from the optical drive, it feels very s-l-o-w.