Silly piece of metal held by the small screw at the edge of the memory door. Just pay attention to how it came out and arrange it the same when you put it back. The screw attaches to the bottom of the keyboard.
Cheers,
its not so silly
You should have switched to a 7200 drive with leopard. Did that with a 1Ghz powerbook last year and it is very usable even with only 512MB Ram.
the 250Gb WD is 5,400 RPM and is the biggest drive available for the PB (IDE HDD)
the 7,200 RPM drives have smaller capacity (160) - the 5,400 RPM does not slow my PB down at all and is not noticable (esp with 1.33Ghz and 1.25Gb Ram!)