I am using at91sam9263 development board. I am using a softpackage from atmel with iar compiler. They give program for mass storage device with Sdram and also Nandflash memory. But my requirment is to add a sdcard peripheral as mass storage device on my host computer. So Please help me to do the process. Can you tell me the steps to add sd card as a mass storage device. If any one having a program for Sdcard as mass storage please reply me.

You will need to get your mmc/sd card driver working, and then attach it to your mass-storage code at the sector read/write abstraction.

There are mmc/sd drivers within the SAM-BA applet source.

I'd show you how, but I'd have to charge.