How is data which was maintained in the registry maintained in Mac? All I know about this is that it is done in pList files. But am not sure how the different areas of registry i.e. HKLM, HKCU is kept in the pList files in mac? Any pointers, suggestions will be helpful.
I believe the answer is that there are two 'Library' folders affecting each user on OS X. One is in /Library and the other is in /Users/MyUserName/Library. Plist fiels stored in /Library affect all users while ones in /Users/MyUserName/Library affect only the user concerned.
If you let us know why you want to know this then we can probably be more help. In general though, there is no single registry, just a large number of plist files pertaining to different programs. Usefully if things go wrong you can often just trash a plist file to fix the issue as the system will recreate them from scratch automatically.
As wikipedia says:
An advantage of this is that corruption to one of these files will normally only affect a single application, whereas corruption of one of the Registry hives can have system-wide effects.
Mac operating systems (OS 9 or OS X) never had a registry! I think you you be be better off with the book Switching to the Mac: The Missing Manual, Leopard Edition. With this book you should almost fully understand the Leopard operating system.