The PDA Editor is a real simple editor that allows you to edit the PDAs (go figure).

As the message at the top of the window states, deletion doesn't work, so if you want to delete a PDA or an email, you need to edit the file in notepad and remove the offending section. You also can't edit audio logs or video cds. That was never a big deal for us because they never changed.

If the Save button is grayed out, the most likely culprit is the .pda file is marked as read-only (or it's in a pack file).