From DD-WRT Wiki
NOTE: During configuration or flashing a device, the only that should be hooked to the device is the computer and power.
These tutorials have content most new users will understand and be able to deploy.
These tutorials require a certain degree of knowledge about general networking that some new users may or may not understand.
This list covers additional software that can be installed on devices running DD-WRT. Note that you can install any OpenWRT package, using ipkg. Additionally more than 1000 packages are provided with NSLU2-Linux Optware packages build specially for DD-WRT.