hi,
What do you mean "flash memory module"? Is it USB PenDrive or SD/MMC/etc card?
Well, according Atmel site, there is some chips you may use:
- T89C5121 with Smart Card interface;
- (A)T89C5122 with USB and Smart Card interfaces;
- AT89C5132 with USB interface;
- AT89C5132 with USB/IDE/ATAPI/MMC interfaces;
- AT89C51SND1C with USB/IDE/ATAPI/MMC/DataFlash interfaces and with built-in hardware MP3 decoder.
Indeed, you also may use another products which have built-in SPI and/or TWI(I2C) interfaces and write software for support some kind of interfaces...

Regards,
Oleg