Accessing flash memory

Hi, im new at the whole arduino thing and i seem to have a project which im not sure i can do.

The arduino mega 2560 supposedly has 256kb of flash memory for the code but say i dont plan to use it all up, would it be possible to use that memory to store data (say in place of an SD card or something)

Or alternatively, can i store data in the EEPROM or SRAM?
this is my first use of the arduinos and im not too sure what to do.

Thanks in advance.

You can use the flash memory to store constants but you cannot write to it using Arduino code. To store configurations and the like, use EEPROM. SRAM is volatile, so after power interruption or a reset the content is lost.

Have a look here at storing fixed data in program memory Arduino Playground - HomePage