PCE for PSP v0.81 has been released. PCE for PSP is TurboGrafx-16 / PC Engine emulator. made by an unkown Japanese coder. This latest release increases the programs stability and fixes some bugs.
Via: EmuCR

Another small update to the Java PSP Emulator. This latest build has updated findings in VfpuState, Plus a small fix in VCMOVT, VCMOVF and VHDP.
Changelog:
Uploaded REV 1098
Log last changes rev1096-1098
Quote:
r1098 Added more tests in VfpuTest. Updated findings in VfpuState: only small fix in VCMOVT & VCMOVF, VHDP confirmed.
r1097 Renamed SWB into VWB (to match prxtool) [...]

PSP Developer Takka has released another update to to his famous unofficial UO gpsp kai GBA Emulator for PSP. We hope Takka continues to tweak and improve the best Gameboy Advance emulator out there. Not many changes in this latest version. added a zoom feature and fixed the file extractino from zips.
UO gpsp kai 3.4 [...]

Been a while, but two recent revisions of DaedalusX64 N64 Emulator have been released by the Daedalus X64 team. This release introduces a number of tweaks and bug fixes.
DaedalusX64 Alpha Revision 407 changelog:
*Fixed GBI1_BranchZ, GBI2_BranchZ uCode commands (Fixes Crash on Pokemon Snap on Phat)
DaedalusX64 Alpha Revision 406
[~]Cleaned up some warnings
[!]Reduced ROM Buffer on Slim [...]

PSP Developer Takka has today released an up to to his famous unofficial UO gpsp kai GBA Emulator for PSP. While his release blog is in Japanese we have gathered the following from the changelog.
* Changed the main font and subfont
* Added missing GBA folder in [...]

PSPHUGO received an update too, as Zx-81 has released version 1.3.0 of his PC Engine / TurboGrafx 16 Emulator. PSPHUGO is a PSP port of the famous Hu-Go emulator.
Changelog:

Audio Track support for CD-ROM (support only MP3 format with stereo 16 bits samples at 22k or 44k rate)
CD-ROM TOC file format support.
Using TurboRip, ripped CD can [...]

Back from a rather long hiatus, Japanese PSP Developer Takka has released an update to his infamous UO gpsp kai PSP Emulator. With the zip bug finally fixed and many other fixes this could just be the best PSP GBA emulator out there…. Oh and welcome back Takka. We look forward to more future updates.
Changelog:

The big [...]

Akop has released an update to VICE PSP, his Commadore 64 aka C64. Akop c64 emulator is a port of the popular VICE commadore 64 emulator. What’s new? Well the sound issue has been fixed, however there are some issues present. the FPS counter sometimes reports incorrect data after frame skipping goes into effect…
Source: Akop’s [...]

Zx-81 seems to be rolling out the updates, as he releases an update to PSPColem. The ColecoVision Emulator for PSP. Version 1.2.1 brings many changes, including improved emulation. Now runs at 60fps at only 133 Mhz. New background music, graphics and added auto-fire support. See below for the full changelog and download link.
* Improve emulation [...]

Zx81 has released a major up to his Atari 2600 emulator, PSP2600. Version 1.2.0 introduces a new and improved interface with new graphics and music. It also now has cheat support added.
What’s new in this version ?
- New graphics from my good friend Horeus
(see http://www.ultimatepsp.fr/)
- New Eboot music
(see http://www.jamendo.com/en/artist/pako)
- Cheat support (but it doesn’t work [...]

Keeping with improving the PC PSP emulator called JPCSP, the team has rolled out another update tweaking the emulator just that bit more. While not a huge changelog, its worth a mention for users following PC Java PSP emulation.
Changelog:
* updating syscalls/nids
Source: JPCSP Forums

An anonymous Japanese PSP Developer has released a new version of gpSP GBA Emulator labelled gpSP 20090413. Its based of the gpSP kai source code and while not much is now as there is no release text. It does feature a number of bug fixes.
Source: pspnfo

The team over at JPCSP.org have released a new version of their popular PC Java PSP Emulator. This new release has the following changes added:

Updated the debugger:

Added address highlighting for jumps and branches.
Replaced the Look and Feel list selection with our own, now register highlighting on the selected line is readable.

RTC updated:

Fixed psp time fromMicros.
Improved [...]

Uberjack has released an update to his Zx Spectrum Emulator called Fuse PSP. In this latest release uberjack has added many new features like, tape rewinding, a tape browser and he has fixed the disk status icon bug.
Changelog:
Version 0.10.0.21 (April 07, 2009):
* Bugfix: Tape/disk status icons should no longer clear when switching between emulator and [...]

Akop has today released RACE! PSP 2.16, RACE! PSP is a Neo Geo Pocket and Pocket Color Emulator for the PSP. New features include a time rewind feature, handy if you just hit the game over screen. You can now rewind a bit and try again.
RACE! PSP 2.16 Changelog:

Time Rewind feature: map ‘Special: Rewind’ to [...]

Zx-81’s release of his ColecoVision PSP emulator PSPColem. This release is possibly the final PSPColem release as it now running perfect with cheat support.
Latest version 1.2.1 – 12th May 2009
Changelog:
* Improve emulation speed (now 60 fps at 133 Mhz !)
* Default speed is now 133 Mhz for green emulation (but you may [...]

Zx-81 has released an update to PSPMO5, the Thomson MO5 Emulator for PSP. This version is a port on PSP of version 11 of DCMO5 which is undoubtedly the best Thomson emulator out there.
Changelog:

- Cheat support !
- Finally fix issue with “Home -> Exit” !
- Add documentation for settings in help menu
- The virtual keyboard [...]

Oops ware has released FinalBurn Alpha 4 PSP v12.4 (FBA4PSP). The PSP emulator which emulates PGM, Cave, CPS1/2/3, Seta, Sega, Konami and MC68000/Z80 based arcade games. While there is no change log for this newest release, we can assume there are improvements over previous versions.
Source: Sourceforge