Here is a comprehensive guide to lamerspeak, aka l337sp33k. The guide fits into a space of 38 by 7 characters, which is pretty damn terse. Of course, it's totally illegible unless you know perl, in which case you more than likely know l337sp33k already..
#!/usr/bin/perl
open(FHA, $ARGV[0]) or die "Input file unspecified or broken";
undef $/; $_ = <FHA>;
######################################
s/dude/dood/ig; s/elite/31337/ig;
s ((f|ph)(e)a(r)) ($1$2$2$3)ig;
s (ck(?:er)?(s|ed|ing)?\b) (x0r$1)sig;
s/w/\\V/ig; s/m/\|V\|/ig; s/l/\|\_/ig;
s/h/\|\-\|/ig; s/f/ph/ig; s/k/\|\</ig;
tr/ieasgtboIEASGTBO/1345678013456780/;
# tr/a-z/A-Z; # this line optional
######################################
print $_;
# This needs some mechanism to apply the regexps
# on lines four and five about half the time and at complete
# random. It also needs to use + in place of 7 to replace
# "t" about one-fifth or so of the time, and to
# inconsistently use l33t in place of 31337, but not often.
# I can't think of any easy way to randomly
# arbitrarily apply regular expressions.
# Yeh, yeh, i know, there are probably like 500 versions
# of this exact script already out there. Whatever.
# Did i leave anything out?