The PS Vita has been out for about around a year, from the very beginning, Sony had promised the ability to play PS1 games on it, but the failed to deliver until a few months later, even then the result was poor, luckily that is where the PS Vita scene comes in, here is a quote from the source:
You can now play your classic PlayStation games with any eCFW exploit.
That’s right, you can now play your classic PSX games with any TN eCFW exploits. The good news is that it works on all firmwares, even on the latest 2.01 official firmware’s psp emu kernel exploit from frostegater that we have yet to release. The PSX support works, however there are some bugs and glitches that come along with it, nothing that apprehends general use. The bad news is that, as of now there is still no sound support, which is sadly an outcome of Coldbird leaving the scene awhile back as he was the only one with sound coded at all. We may see it later on, however seeing it any time soon would be unlikely as it would take some incredible work to get it done.