Lots of thanks to byemu for providing the source and allowing what I think is the most complete version of a nes emulator for PSP (would be perfect with 1.20beta2's wifi support but...).

A google-translated readme file is included, but here's a list of features since Ruka's nesterJ 1.11:

Changes from 0.61 (based on nesterJ 1.12 by Takka, based on nesterJ 1.11 by Ruka)

From suloku:
- Added rewind mode coded by Davex
- Added mirror and rotated screen modes by Davex
- Added sepia color palette by Davex

From byemu:

- Added support for a LOT of boards and mappers, including mapper 163 (NJ063 Final Fantasy VII Advent Children among others)
- PAL-NTSC selector
- Added Chinese interface language
- Added FAT ROM read mode, which enables Chinese filenames while browsing
- Added a new cheat function to make changing games easier.
- ROM support up to 4M
- Increased exception handling, prevention of reading the game crash
- Roms can be deleted. Press [] (square) in the rom list interface.
- Added and increased a custom rom database (byemudb.dat)

From 1.12 by Takka:
- Ported to 3.xx firmware (full user mode)
- Fixed sleep mode issues
- Fixed saving issues (sram and states)

Notes (google translated):
- DQ4 (1 of the Chinese Version) to read two times before the game
Three Chinese version of the Central Plains of Bazhe alien to read two times before the game.

- 2 Chinese version of heaven and earth devour some need to select PAL standard, and then re-read the ROM, can be a normal game, or else they will Huaping
Street Fighter version 9, please choose NTSC / AUTO format, then load the game, otherwise the game will be black and white more than 10 seconds to enter the game
Red Fort, select PAL and then reads the ROM, otherwise they will be black and white more than 10 seconds
Select PAL version of Street Fighter 4 will Huaping, select NTSC / AUTO format
South crystal game please frequency is set to 333, such as "Tomb Raider", otherwise it will crash just like the same card


Credits:

- ruka (original nesterJ PSP)
- byemu (nesterJ plus)
- takka (nesterJ 3.xx port)
- davex (rewind and screen modes)
- sakya (exception handler)
- nester and nesterJ authors