Update #3: Shylph has released NeoCD File Selector for use with the NeoCD PSP emulator below.
Update #2: NeoCD v0.1b has been released today! Updates include fixes to both the D button and VSYNC issues.
Update: Today the previously-rumored NeoCD v0.1 and source code have been released! Currently it runs (as pictured) via the EBOOT PBP Interpreter with further PSP implementation and development to follow soon. Nice to see it finally released!
Rumor has it a Neo-Geo CD emulator for the PSP is in the works! No details yet on a release, however, the screen capture to your right displays it running via EBOOT PBP Interpreter,the PSP emulator for PC, which is available in our on-going PSP Utilities Forum thread. Cool stuff!