Carlos is working on his latest project called CAML XML Editor (available on gotdotnet).
“At the moment he is a simple XML editor that allows simultaneously to publish the code by fragments (use the context menu in editor) that can are validated themselves. Also has a HTML preview to show the HTML code generated.”

“And a little CAML generator, you can select any CAML then you has the correct XML, if you select a reference in the XML you can expand it using the context menu.”
Download here