Se non capite lo slang usato in certi newsgroup... 
You've probably already seen this, but in case you haven't you should check out A parent's primer to computer slang. I'm sure my readers are pretty fluent already in l33t-sp34k, but if you know some n00bs (note: i use it affectionately) who need some education you now have a concise source to help them with.
Fun sections include:
- Key points for learning leetspeek
- Numbers are often used as letters. The term "leet"
could be written as "1337," with "1" replacing the letter L, "3" posing as
a backwards letter E, and "7" resembling the letter T. "0" (zero) will
typically replace the letter "O."
- Characters of similar appearance can be used to
replace the letters they resemble. For example, "5" or even "$" can
replace the letter S. Applying this style, the word "leetspeek" can be
written as "133t5p33k" or even "!337$p34k," with "4" replacing the letter
A.
- Letters can be substituted for other letters that
may sound alike. Using "Z" for a final letter S, and "X" for words ending
in the letters C or K is common. For example, leetspeekers might refer to
their computer "5x1llz" (skills).
- Rules of grammar are rarely obeyed. Many
leetspeekers will capitalize every letter except for vowels (LiKe THiS)
and otherwise reject conventional English style and grammar.
- Mistakes are often uncorrected. Common typing
misspellings (or typos) such as "teh" instead of "the" are left
uncorrected and may be adopted to replace the correct spelling.
- Non-alphanumeric characters may be combined to form letters. For example, using slashes to create "/\/\" can substitute for the letter M, and two pipes combined with a hyphen to form "|-|" is often used in place of the letter H. Thus, the word "ham" could be written as "|-|4/\/\."
As well as ways to tell if your kids are up to illegal activities.
Other links point to further bits
of netiquette for those few people who haven't discovered the intarweb yet.
Source: ph34r my l33t skillz