The software to control this device is hosted at Sourceforge http://sispmctl.sourceforge.net/.
Having recently acquired one of these devices this page is intended to document building it for OpenSlug 3.10.
packages installed using ipkg are slugos-native, libc6-dev, libusb, libusb-dev
make returns this error
armeb-linux-gcc: 2.3a": No such file or directory
but it appears that the code compiles as make install works when run as root.
The sispmctl command works letting me switch the power to each socket on and off.
--- Note Sebastian Kraatz: sispmctl compiles without errors using Debian on the NSLU2, works like a charm. I'm using it to switch on power of my laser printer when a print job arrives: http://www.skraatz.de/gadgets/debian-etch-auf-dem-nslu2