now that's a LOT ur asking for in one little post m8 but check out the beginner's faq section there's a some tutorials there also search youtube.com or video.google.com for guitar lessons goodluck
The way to learn chords and switching between them is a step by step process.....learn chords in two's. i.e. learn A and B ....and keep practicing them the switching will only start happening when you practice hard!
learn the chords according to their family. Dont learn like one after the other(A,B etc). For example C chord family is C,F,G7th. Try learning one family at a time and switch between the individual members of the family. That way it will be helpful for you in future when you play songs.