Have you looked at _Essentials of Programming Languages_? It focuses on interpreters rather than compilers, but its a good place to start if you're not clear about how to lower some construct (eg, closures) that your syntax defines but which don't directly correspond to something in vbs.
On a side note, is there any particular reason you wouldn't want to use a lispey syntax? You get a lexer for free, and could implement whatever domain-specific constructs you like as macros.
