There is now a guide for those people with the dreaded WRT54G/WRT54GS version 5 or 6 Linksys routers. Until now it was very difficult/impossible to upgrade these routers to third-party firmwares. The guide will walk you through the steps you need to take to install DD-WRT on your Linksys router.
Previous versions of the WRT54G/WRT54GS routers were not plagued with this problem because they did not use VxWorks. When Linksys decided to install VxWorks onto the more current routers it became very difficult to upgrade them, until now. They eventually released the WRT54GL which is essentially the WRT54G version 5 but users are able to upgrade the firmware because it lacks VxWorks.
At least buyers that are initially unaware of the version differences will now have the opportunity to upgrade their routers!