Question : Problem: How can I read a Macbook Pro hard disk on a PC

I am very proficient with PC's, but I know next to nothing about Macs.  Recently a client handed me a MacBook Pro computer that they say was briefly dropped in water.  It does not power up.  I have instructions that explain how to remove the hard disk.  The client just wants to know what the kid has been doing while away at boarding school.  
1.  Is it just a standard 2.5 ATA (IDE) hard drive?
2.  Once I connect it to a PC using an adapter, what software would I use to test and analyze it?
3.  Without any knowledge of MAC file structure, will I be able to learn anything about the content?

Answer : Problem: How can I read a Macbook Pro hard disk on a PC

Contrary to the above comments, the simplest method is to install MacDrive.  It's been around for many many years.  I came from a pre-press shop.  We used it on the PC workstations.

Mac users who boot Windows on their Macs can use this to access their drive without a complicated sharing method.

http://www.mediafour.com/products/macdrive/


To answer your questions:

1.  Is it just a standard 2.5 ATA (IDE) hard drive?
No.  SATA.  See here for instructions on removal (voids warranty, of course):
http://www.extremetech.com/article2/0,1697,2119528,00.asp

2.  Once I connect it to a PC using an adapter, what software would I use to test and analyze it?
Not sure what you mean by "test" or "analyze".  If you want to know if it will boot up, you will need to install in a known-working MacBook Pro.

3.  Without any knowledge of MAC file structure, will I be able to learn anything about the content?
Short answer: No.

If you're looking for forensics info, you can start here:

http://blackbagtech.com/products/software.htm
http://www.ilook-forensics.org/  <<--government/military entities or contractors

List of resources:
http://homepage.mac.com/macbuddy/ForensicGuide.html

Since the owner (assumption?) of the computer is requesting the information, this would probably be deemed acceptable in most jurisdictions.  Without the owner's explicit permission, or without a court order, it would most likely be illegal.  Spying on a family member is a grey area when the ownership is questionable and the data does not belong to the person requesting it.