could anyone recommend any sites on the net or books pertaining about for-mentioned subject.

I got a lot out of "Winning Poker for the serious player" by Edwin Silberstang, which I borrowed from a friend. It covers other variants as well though, so if you want a specialised Holdem book it may not be the best around. The Smartgambler bookshop has various poker books advertised.

All the poker rooms advertised on this site, (Party, Pacific, etc) are reputable. Click on any of the links. In my opinion Party is best because of the sheer number of players... you can always find the kind of game you want.

I also play on Noble which is a good site, but sometimes if I want to play a sit and go I register and am still waiting for a full table ten minutes later... so I unregister and go to Party and get a game straight away.