Hi everyone on Friday my co-partner and I from work decided to update a Linksys's wirless router model:WRT54G V8.0 frimware to a DD-WRT firmware update,and I was very amzed how it turn this $50 Wifi router into a $600  wireless router , it now has extra added features.
IMPORTANT:If you are going to try this please READ THE GUIDE.
Below are the added features that you will expect to see once you upgrade.check out there Site to see what other vendor's are supported. I do plan to buy the current WRT54GL which is Linux base router if you have an old one I think you will benifit once you read this Site.
link to DD-WRT:
http://www.dd-wrt.com/wiki/index.php/What_is_DD-WRT%3F

Supporeted devices Site:
http://www.dd-wrt.com/wiki/index.php/Supported_Devices

Features:

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802.1x Extensible Authentication Protocol (EAP)
Access Restrictions
Ad Hoc
Afterburner
Client Isolation Mode
Client Mode (supports multiple connected clients)
DHCP Forwarder (udhcp)
DHCP Server (udhcp or Dnsmasq)
DNS Forwarder (Dnsmasq)
DMZ
Dynamic DNS (DynDNS, easyDNS, FreeDNS, No-IP, TZO, ZoneEdit, custom, and others)
Hotspot Portal (Sputnik Agent ,Chillispot)
IPv6
JFFS2 (JFFS2)
MMC/SD Card Support (hardware modification required)
NTP
ntop Remote Statistic (ntop)
OpenVPN Client & Server (only in -vpn build of the firmware)
Port Triggering
Port Fowarding
PPTP VPN Server & Client
QoS Bandwidth Management
QoS L7 Packet Classifier (l7-filter)
RFlow
Routing (BIRD)
Samba FS Automount
Syslog
Rx Antenna
Tx Antenna
Show Status of Wireless Clients and WDS with System Uptime/Processor Utilization
Site Survey
SNMP
SSH server & client (dropbear)
Startup, Firewall, and Shutdown scripts (startup script)
Static DHCP
Style (Changeable GUI; v.23)
Supports New Devices (WRT54G V3, V3.1, V4, V5 and WRT54GS V2.1, V3, V4)
Telnet server & client
Transmit Power Adjustment (0-251mW, default is 28mW, 100mW is safe)
UPnP
VLAN
WOL (Wake On Lan) (WOL)
WDS Connection Watchdog
WDS Repeater Mode
Wireless MAC Address Cloning
Wireless MAC Filter
WMM (Wi-Fi MultiMedia)
WPA over WDS
WPA/TKIP with AES
WPA2
Xbox Kaid

It's amazing what you can cram onto these embedded devices. I was involved with the the Neptune354 project helping build a custom firmware for the Linksys WAG354G.

Most consumer embedded devices are limited by disk space, which is why the USB support on many linksys routers allowed for cheep storage upgrades. Sadly the WAG354G lacks this, but if anyone is interested the new version supports NFS :-) Details are on Marco's site...

http://cyberstorm.altervista.org/

Jimbob