Although LR4 is fairly intuitive, there are a lot of details that have to be explored. A book recommended to me is Scott Kelby's Lightroom4 book for digital photographers. It is a paperback, has lots of information, organized in a fairly logical order. The index is good, too - something people don't always worry about, but invaluable when looking for something specific. Lots of illustrations to help with understanding.

I ordered it online, from Barnes and Noble. There might be somewhere you can get it over there.

Enjoy!