Slackware has a new official port for the ARM architecture, by the name of ARMedslack, which has recently released the port of Slackware version 12.2.
ARMedslack began in 2002 by Stuart Winter, with the primary goal of providing a full Slackware port for ARM desktop machines - initially targeting the Acorn StrongARM RiscPC, and later embedded devices.
Slackware ARM now supports native installation using the regular Slackware installer on the ARM Versatile board (via the QEMU emulator) and the recently announced embedded device: the Marvell SheevaPlug.
Slackware ARM version 12.2 is built for armv4, little endian, "legacy" ABI. A new port to the EABI is already underway and expected to be available in "-current" form within a few months.
The project's homepage has more details.