Divineo released the Neo-PSP PAD 8 in 1 inc. 4GB Microdrive yesterday.
PSP Updates summed up the features of this device quite nicely:
It adds to the PSP functionality in three different categories, Memory, Battery, and Ergonomics (how it is held/comfort of playing). For memory it allows the use of more than just the standard Memory Stick Duo cards. It allows the use of MMC, CF, and MicroDrive cards as well. It supports a total of 4 gigs of memory.
The NEO-PSP Pad finally allows the use of normal AA batteries to power your PSP. It also has a built in charger for your Ni batteries. You can do this with many different DC charging devices, including USB. The NEO-PSP Pad protects your PSP with anti-shock protection, and it converts your PSP into a more PS2 Dual Shock controller feel.
The device will set you back $174.99 US though it might be worth it for all the functionality assuming it works as advertised.
Source: PSP Updates