Welcome to Pocket PC Thoughts.
Are you referring to the process of formatting the card for access? Because a true software-locked MMC is about as rare as the dodo.
Most cards should already ship pre-formatted, but if your card wasn't endowed that luxury, you have two basic options:
(1) Insert the card into a card reader attached to your PC. It will appear in My Computer. From there, right-click the drive icon and select Format.
(2) Insert the card into your Pocket PC, and use a third-party application such as Spb Pocket Plus or Resco File Explorer to format it.
If you're after something totally different though, let me know.
