compact flash and sd memory

i have 2 sticks of 256 mb of compact flash memory and i was thinking of getting an expandable mp3 player, likely the Rio expandable ones. its says on the site that those mp3 players can support sd and mmc, so does this mean that i can use cf memory cards on an sd expansion slot?

srry, wrong topic. can someone please move this to storage?

Nope, you cannot use a compact flash card in a SD or MMC card slot. The cf cards are too big to fit.