There have been many discussions on how to do this, as everyone will know by now it's not normally possible to transfer the config from another router on a new one.
This is a way to do this which will quite probably work without the hassle of other methods suggested! You need to save a file somewhere on or off the router, try the following from the command line:
nvram export —set >config.txt
This outputs the setup in useable text form, each line beginning with "nvram set".
nvram set pci/1/1/pa5ghw1a0="0x163a"
nvram set wan_dns=""
nvram set wl_wmf_bss_enable="0"
nvram set wl_nreqd="0"
nvram set pci/1/1/maxp5ga1="0x40"
nvram set script_usbumount=""
nvram set wds_save=""
nvram set pppoe_service=""
nvram set ddnsx0=""
nvram set lan_wins=""
nvram set wl0_rxchain="3"
nvram set pci/1/1/pa5glw0a1="0xfe9a"
1) To restore is "nvram import config.txt". This *may* work to import to another router.
2) If you paste "nvram export —set" into the "Tools/System command execution box in firmware based on Teddy Bear's builds, it will give you the file onscreen, these lines can then be pasted into another router.
3) You could also write a small script to send it to a PC cifs share using the Scheduler.
4) It is actually very easy to set up just the important basic config by hand, but cherry pick the variables from the text file that are a real pain to do manually (large Static DHCP and Access restriction lists in particular).
NB - This has the added advantage that you don't re-enter any old unused variables from some long forgotten setup. Often you can reclaim several kilobytes of NVRAM. If you are running short on NVRAM space, try doing this.