Reading waw from MMC/SD card with PIC 18F4550

Hi all,
I have a project about microcontrollers.
I have to design a micricontroller based circuit reading music files which is waw format from MMC/SD card to 8 or 16 bits (it doesn't matter) DAC over some port of PIC and then playing it, additionally displaying the name of waw file (which is playing that time) on 2x16 LCD. And of course there will be some buttons to control the circuit in order to play, pause, take forward or back the songs.
I am very new at PIC progmamming but I am good enough at C programming language. I will use C language with mikroC compiler to program the PIC already.

Are there anybody to suggest me some advices about my project ?

And my real trouble is reading and writing data from/to MMC/SD card.
I know there are some prepared functions in mikroC libraries. But I want to know their contents in order to understand better how MMC/SD card works.

Briefly How does work MMC/SD card with PIC (18F4550)?

I hope I could tell my troubles understandably..

I am wating for your advices.. If you can help me I will be very happy
thanks for reading my writing

The exact same thing has been done
here
Swordfish Wiki | SwordfishUser / SDMMCWavPlayer browse

Thank you Someone Electro.
It will be very useful for me especially the circuit diagram. I don't know basic language but I can study on it some.
Even so If you know the same program written in C languge (mikroC would be better) at anywhere plase can you write me.
Thank you again Someone Electro thank you very much

I did a wave player in C
uC Hobby » Blog Archive » dsPIC WAV Player

But mine can play wav files from 8 to 48Khz at 8 or 16 bit and it uses a faster dsPIC30 MCU. Also it uses a fast PWM for a DAC. If its run at 3.3V it needs next to no external components.

Thank you very much Someone Electro. Thank you very much.