Eric Burke posts on his O’Reilly weblog concerning the new version of his tool, “AntGraph”:

AntGraph uses an XSLT stylesheet to convert any Ant buildfile into a “dot” file, which is then converted into a GIF image using “Graphviz”: from ATT labs.

To be honest I think if your Ant files ever got complicated enough for this tool to be really useful then I’d suggest rewriting them, but it looks cool anyway.