I am trying to write a grammar in EBNF (barring a really good reason, it has to be EBNF) and am looking for a couple of utilities for it - if there's a GUI interface that can make one, that would be great, but the thing I'm looking for most is something that can check the grammar, for instance to see if it is LALR(n), and if so, what the value of n is. Do such utilities exist? Are there any other useful grammar-writing tools I should know about (I'm not looking for parser generators).
Taking Steven Dee's suggestion one step further, you might want to check out ANTLRWorks, which is an interactive GUI development tool for ANTLR grammars.