I love the units from Linksys, whether it is an access point, or in our case a USB NAS, they are easy to hack and play with.
In the past couple of weeks, I have been messing with my NSLU2 at home. I have upgraded it using Unslung firmware. It is designed to allow you to expand the capabilities of your NSLU2, without losing the standard product functionality and still retain full compatibility with stock Linksys firmware.
Unslung is a cool piece of software, it is booting a 20 GB external USB drive (it can also use a USB key or any other USB external drive). Now I am running a miniture Linux box. I have installed mt-daapd (allows you to create a share that is visible by Itunes) and Asterisk (VOIP telephony server). I have copied all my mp3 songs and they are accessible from any computer around the house.
Yesterday, I went a step further, removed the resistor that down clocks the CPU, now it is fully 236 Mhz.
I love it