Internet Embedded

Hellow Guys.

My Name is Tiago and i'm from Brazil.
I'm looking for references about creating an embedded ethernet
microcontroller. I'm concluding the Computer Science Course and i
intend to develop a small controlled board with a serial connector...

My plans are connecting the serial port in the ethernet using
At89s52(8051 microcontrollers family) and a RJ45 connector...

There are some options available in the marketing, but these options
are a lot expensive. I would like to develop my own solution for this
problem but the references i found didn't increase some significant
knowledge.

I really apreciate your atention.

Thanks.

Tiago Samuel

.