Hi,
I'm not sure about my WRT54G configuration. My ideia is interconnect a microcontroller with the WRT54G using RS232 (This already is functioning.) and after this, send and receive information from a Wireless PC.
Then I configured my connection between the PC and router with an ad hoc connection. My NVRAM:

wl0_net_mode=mixed
wl0_infra=0
wl0_ifname=eth1
wl0_mode=ap
wl0_gmode=1
wl0_ssid=GSIM
wl0_closed=0
wl0_macmode=disabled
wl0_channel=6

I have used mode acess point, because When my device will be on, my PC, PDA, and so on, can be able to connect it.
I want to do something like a wireless station to monitoring something. What is the usual config? 
 
Wesley