you have to port them if you want to use them. There's a reason Squeak runs binary equivalent on Windows, Linux, Solaris, Macintosh, Mac OS X, the Sharp Zarus, and some other little handheld gadgets. The core VM is portable but there are stubs you need to do hardware/filesystem/network/display/input device interfacing.
FWIW, there have been a number of embedded Smalltalk projects over the years.
You might not be able to afford Squeak on your smaller devices. You may be able to afford PocketSmalltalk though. There is some info here: [link|http://www.iutc3.unicaen.fr/serge/62|http://www.iutc3.unicaen.fr/serge/62] or [link|http://www.pocketsmalltalk.com/|http://www.pocketsmalltalk.com/]