Rather than try to learn it all via IRC, your best bet is to get a book (O'Reilly do a number of Linux books - check our Book Review
section) and to install Linux and try it out. Anything you learn on IRC is lost in the ether when you disconnect.
As far as hacking goes - I assume you mean investigating source code to see how it works/see how it can be improved? You will need to learn programming and networks - again O'Reilly have a number of good books on programming languages, security and networks.