Generally, it's just in London, but most people will know what it means even if they wouldn't use it themselves. It's very colloquial but not vulgar. :)

Australians will also know these forms of rhyming slang, but we also have our own expressions: "have a gander", or "have a squizz". Austin Powers talks "English English" in front of Americans (and yes, what they say actually makes sense): http://www.youtube.com/watch?v=PgPH0tYXJrA

Rhyming slang has several common expressions............. Butcher's hook = look ............... Sky rocket = pocket .............. ............ As Lewis says, people will understand, but maybe few will actually speak this way.