HOWEVER, there are some undocumented points that are garnered from my own experience opening up my 15 inch 1.83 Ghz MacBook Pro to replace its hard disk with a bigger 160GB model.
First, follow iFixit's guide unscrewing all the screws that they tell you to, and get to the part where you're supposed to take off the top plate (that's what I'll call it - its the piece that has your keyboard). It should look like this:
Then you'll soon find that the the trickiest part is getting the side closest to you, out. iFixit says something like rock it side to side. Well, I found that the left part came off after a little bit of rocking, but the right side and the area above the screen latch button was quite stubborn. After some jostling, where I thought I'll break something along the way, I managed to lift the left part out and somehow slide the right side backwards a little towards the screen and off came the top plate. You gotta pop that connector like they say on iFixit, if you wanna remove it completely.
On closer examination, here's why its such a pain to remove the right side:
Notice the four rectangular holes near the front edge? Good.
Next take a look at this:
This is what's below the top plate. Notice those grey plastic tabs? They actually fit into those rectangular holes. Here's a close up:
The grey plastic tabs looks like this:
I guess an alternative would have been to pop off the top plate right off, leaving the grey tabs hopefully still in their respective holes. But because these joints are quite tight, it also leaves me to wonder if the thin ends of the grey plastic tabs will hold it firm enough to remain in the hole, or simply snap.
Anyway, if you do indeed take apart your MacBook Pro - at least you now know why there are parts of the top plate that seem like they ain't coming out - even though you've already taken out all the screws that the guide says.