I know it sounds ambitious but our client requires a PDF Reader of his own with some selected functionalities. Can anyone guide me to some good tutorials for paving the way to start this development?
I guess I need to clear some pdf basics and start from scratch OR i would be happy if there is any library which i can use directly and only modify the controls at my will.
In terms of specific Android implementation, I really can't advise you there, I'm afraid.
However, there is a lot of PDF viewing software available that is open-source which would allow you to see the underlying code to learn from.
One example is PDFedit, which is also an editor, but there are loads on SourceForge or Google Code you could have a look at.
This Wikipedia section has a list of multi-platform development libraries which could help you. There is also a bunch of PDF software, much of which is open-source. Perhaps you could find a simplistic one and have a look at how it parses PDFs.