I've had the opportunity to set up a small network consisting of two Linksys WRT54G routers running DD-WRT. The client router was set up to run as a bridged client. The instructions from the web were confusing. Fortunately using the configuration menus of DD-WRT was easy. I'll post the instructions in a future post. After a couple days of running flawlessly, the master router would lose connectivity to the client router even though the client router was running and pingable by cdevices attached to the client router. I did not debug this and decided that running wires to connect the two routers was a much simpler solution.
In summary, I do not recommend using DD-WRT on a Linksys router to expand your network. When the network does down, wireless connections introduce another component to debug (or said in another way, it introduces another level of potential frustration).