The whole leat speak crazy has kind of faded away. I don't blame them, howewever. What started as a few simple numerical substituions exploded into an orgiastic bloom of complicated dialects.
This is actually quite a shame, because I think that leet-speak would be a great way to enhance online communication. What is needed, then, is a leet-speek foundation, the purpose of which would be to catalogue and study the language.
The question, however, is what dialect of leet should we choose from? I opt for a a simplistic approach. The ideal dialect of leet derives it's power, like all languages, from intelligibility. Therefore, the amount of substitution cipher employed should allow for cultural internet heritage, as well as understandability.
This particular dialect, therefore, is more subdued than many of the crazy forms that have recently come about. I find that one of the reasons for the death of leet was the over-the-top outrageousness of some flavors of leet.
In contrast, southern leet is far more conservative. The rules for this dialect follow:
a -> 4
e -> 3
t -> 7
o -> 0
y -> j
i -> 1
ou -> 00
c -> k
j00 N33D 70 KH00S3 j00R G4M3S W1S3Ly, d00d!
Of course, having said all this, do with it what you wish.