The 2nd NSLU2 arrived and I started hacking it. I installed SlugOS, moved it to a 2GB flash drive and then installed gcc. Next, I installed HeyU, compiled the source right on the Slug. Then I installed the Edgeport driver ( kernel-module-io-edgeport ) and put the Edgeport/2 on one USB port. It was recognized according to the syslog messages in /var/log/messages, but I couldn't get HeyU to recognize CM11A connected to the Edgeport. I tried a whole bunch of things - reflashing SlugOS, recompiling Heyu, reinstalling the drivers, installing Misterhouse, trying a W800 on it, etc. In the end, it appears the Edgeport driver doesn't work on the NSLU2.
I headed over to Fry's and picked up an Airlink USB to Serial adapter. It has the PL2303 chipset that is known to work on the Slug. I installed the kernel-module-pl2303 driver and presto, everything worked. I'll need to add a USB hub later since this, unlike the Edpgeport/2, only supports 1 serial port. Now, I need to work on a HeyU lighting schedule.