PSP World Writes:
"The Micro SD to Pro Duo adapter from Photofast allows you to put two MicroSD cards inside your PSP at the same time. Since MicroSD sizes range all the way up to 16GB per card, that means you can fit roughly 32 GB of storage on one of these bad boys.
The best news? The card works super fast, so there is almost no additional lag while copying over files. "