I finally got EnigMail working with native Mozilla on NetBSD/i386 -current (latest Mozilla 1.5.1 from pkgsrc with enigmail 0.82.2). I uploaded the XPI files here. To install the XPI files, run Mozilla as root, open the directory that contains the three XPI files in the browser and click on the files to install them, in the following order: The IPC module, the enigmime package and finally the enigmail package. Finally start Mozilla and configure enigmail as mentioned on the EnigMail website.