I should note that I had difficulty getting changes to the pool settings to stick via the webgui, so I had to ssh in and configure the pool information with nano /var/www/accout.txt then shutdown -r now to reboot
User/pass is root/admin for ssh on these guys. You should have a number written on your unit and on the SD card. That is the last quad of the 192.168.1.xxx address of the system.
For changing a pool address, stop mining first via Webgui, then change a pool address and save. After that, start mining again.