Jeff Mitchell has updated his CaSTaway for the PSP. CaSTaway is a great Atari ST emulator. It is in early stages, don’t expect too much from it. Changes:
Added a basic disk picker menu, full screen smoothed scaling and an on-screen keyboard so you can operate menus; still not fancy but we’re getting there!
AEP-Emu (DE/EN)
DMG Page (DE)
Indie Retro News (EN)
Retroguru (EN)