I've tried DD-WRT on my WNR3500L and was unable to configure it to use USB Share through Samba. DD-WRT installs fine and sharing an EXT3 USB drive is also ok through the default FTP, but the problems starts when optware is used for Samba.
Most of the guides arround extra software to DD-WRT is using Frater's 'Optware the right way' and it installs ok, but it isn't working optimal. I've tracked it down to something arround Linux kernel version compability where the WNR3500L is using K2.6 and the optware is made for K2.4. Frater's package is also using Samba2 and it makes a miss match for my european characters, and that should work better with Samba3.
Has anyone a good solution for the WNR3500L where USB Shares can be mounted and shared/browsed with Samba and FTP without character miss match. I'm using optware for rsync as well so that would have to work to.
This is also posted at http://www.dd-wrt.com/phpBB2/viewtopic.php?p=392465#392465
I dont think SAMBA is fully supported in DD-WRT yet .. Also if u wish u can use Netgear's default f/w for ur WNR3500L .. it supports SAMBA .. Also u can see the following article 2 find how 2 do this ...
http://www.myopenrouter.com/article/13385/Configuring-USB-Storage-SAMBA-...
You can use in as a NAS, storage for a FTP server, yes by the use of Optware to run external programs like torrent ehr software, samba for sharing files to your network, share a USB printer with your network...The list of possibilities is long, it just takes a little research.