interfacing of wifi shield with mega

http://www.protocentral.com/103-wifi-shield.html

This is the wifi shield that i am currently using with arduino mega. Can someone please tell me how can i interface both the boards?

I want to transfer a file from sd card module to a PC with the help of shield. Please let me know if someone have implemented this. (And obviously the code for that might help.)

Possible info sources.

http://www.seeedstudio.com/wiki/Wifi_Shield

http://www.seeedstudio.com/wiki/images/b/be/WiFly-RN-UM.pdf

https://www.google.com/search?hl=en&as_q=wifly&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=&as_qdr=all&as_sitesearch=http%3A%2F%2Farduino.cc%2Fforum&as_occt=any&safe=images&tbs=&as_filetype=&as_rights=