Do you need a lot of space?
EEPROMs not quite enough? How's 1GB sound?
This is a socket used to interface to SD (Secure Data Disk) and MMC (Multi Media Card).
We used it to test out our 'PIC to FAT16 on SD' routines. The SD/MMC cards use a very simple SPI serial bus as well as a 4-bit proprietary bus.