This has been a long time coming, but my schedule is just now starting to free up. I have updated psx4iphone to also support the 3.1.x series of firmwares. Included in psx4iphone v1.1.0 is a fix for a bug causing the non-scaled landscape screen to display properly.
Don’t expect too much difference in performance. This emulator will still require an iPhone 3gs or iPod Touch 3rd Gen to really shine. I will be working more on this emulator as I get more free time.
You can download psx4iphone from the ZodTTD Repo which is built-in to Cydia via the included community sources package. This means it is also available via RockApp, Icy, etc. Brief installation instructions are provided within the package info.
If you run into any issues with psx4iphone v1.1.0 feel free to ask for support via the comments. Just remember, don’t ask for ROMs/ISOs or where to get the BIOS.