The new bytecode in Java 6 explained

For a long time, I've been looking for a cogent explanation of the new bytecode, called invokedynamic, that is being introduced in Java 6 (Mustang). This bytecode facilitates calls to scripting language methods in a context where data items are not strongly typed. Beyond that brief description, though, it's hard to find much info. Here, however, is a link that gives a good overview of the role of this bytecode and where things stand now regarding its implementation.