Leet words can be expressed in hundreds of ways using different substitutions and combinations, but once one understands that nearly all characters are formed as phonemes and symbols, leetspeek isn't difficult to translate. Also, because leet is not a formal or regional dialect, any given word can be interpreted differently, so it's important to use discretion when evaluating terms. The following serves as a brief (and by no means definitive) introduction to leet through examples.
http://www.microsoft.com/athome/security/children/kidtalk.mspx
Microsoft -> A parent's primer to computer slang - Understand how your kids communicate online :-) 
