Please note the following information is based on my personal experience and knowledge only. You have been notified on the risk involved, I'll not be held responsible for any causes to your device either before, during or after Tomato flashing, you are doing this at your own risk.
Please read through the following before flashing.
Official website : http://www.polarcloud.com/tomato
Supported devices : http://en.wikibooks.org/wiki/Tomato_Firmware#Supported_devices_and_revisions
Installation Guide : http://en.wikibooks.org/wiki/Tomato_Firmware/Installation_and_Configuration
If you like Tomato, please make donation to them to show your support and appreciation.
Those Tomato developers really spend a lot of efforts in making this wonderful firmware to benefit us, a small donation and give-back may not means anything to us, but it will certainly recognise their great efforts to continue making better firmware for our routers!!
By flashing the router with 3rd party firmware like Tomato, individual owner must aware that it will void the manufacturer warranty, risk for unable to flash back to original manufacturer firmware, possible to the extend of bricking the device!