Mr. Halburge.

The first time I decided to use an 8051 (or 8052) core µ-controller I downloaded the tutorial right off of this site. Dig around the FAQs and other pages listed right there on the left side of this screen and you will be off to a good start. You will also want to study the chip specific details from your chip's manufacturer's data sheets. Finally, most of the manufacturers have a wealth of information free for downloading right on their website.
As for mastering the programming, you'll need to learn what the chip can do first. I would suggest that you write a few simple to increasingly difficult programs directly in hex. My first "Hello World" circuit was nothing but a ripple counter and I used Hyperterminal to program the FLASH. Of course when you start doing something more complex you will want to use a compiler, or maybe even an IDE (integrated developement environment), but the intimate knowledge of the µ-controller will still serve you well. And, when it is necessary, you will have the ability to exercise the lowest possible level of control over your routines.
Anyway, that's my two cents worth. Good luck.