I've been aiming to set up my router with a special version of Linux. It makes it handier for certain things. Trouble is, the newest routers fron Linksys are hobbled. You need formware version 4 or below to do anything special with them. The best way to tell which version is which is by looking at the first four characters of the serial numbers (which can be found on the bottom of the retail box). Here's the breakdown:

CDF0 = wrt54g v1.0
CDF1 = wrt54g v1.0
CDF2 = wrt54g v1.1
CDF3 = wrt54g v1.1
CDF5 = wrt54g v2.0
CDF7 = wrt54g v2.2
CDF8 = wrt54g v3.0
CDF9 = wrt54g v3.1
CDFA = wrt54g v4.0
CDFB = wrt54g v5.0

Anyway, maybe I'll head out to the Circuit Shitty and pick one up for playing with. And now I have this handy reference for when I do! Ain't that just something?