Information on the most well-developed and widely-used ports is on Downloading Squeak.
Here are other Squeak ports we know of:
Tim Rowledge ported to Acorn RISC OS for the Acorn Archimedes, Iyonix and now Raspberry Pi, plus the DEC Itsy http://www.research.digital.com/wrl/itsy, the first unix-with-framebuffer attempt and the precursor to the iPaq range, plus (along with Craig) the Interval Research MediaPad. And the exobox unity platform.
