RDN
abbreviation: ROM Database Notes, file used to store User Notes browser field
Do the following to achieve what you want:
Create the file Project64.rdn by right mouse clicking and selecting New.
Select the Text Document options and you will then have New Text Document.txt
Change the New Text Document.txt name to Project64.rdn
Now go to Options and then settings in PJ64 and click on the Rom Slection Tab.
Scroll down on the Avalible Fields Section and select Notes (User) and then click on the Add button and press ok.
now open the Project64.rdn in your Text Editor (WordPad, Notepad) and then add the roms information.
[Game CRC]
Internal Name=Game Internal Name
Note=user notes here
Example:
[ABA51D09-C668BAD9-C:58]
Internal Name=40 WINKS
Note=user notes here