This command line shows you a few details:
$ pdftk … dump_data_fields
Not enough details for me.
What about CAM::PDF?
It comes with a couple of nice sample utilities (the bin/ subdirectory), one of them is called listpdffields.pl . It also does not show me enough details, but I think I will enhance that one.
Update / 2010-12-11:
Yes, CAM::PDF works very well for me. I wrote another article on that.