If you have added your own fields to any of the templates that use the Project tracking features, you may have noticed that your fields don't show up in the new or edit item pages.
Just turn on Content Type management in the list settings page and then click on the Project content type to add your existing list fields to the content type.

 

If you have tried the Bug Database template:
Don't forget to run stsadm.exe -o copyappbincontent
as per the Bug Database template and instructions:
http://www.microsoft.com/downloads/details.aspx?FamilyId=C72D23AF-F556-47AA-A6F2-0027246A9928&displaylang=en
(thanks to Charles Wieland for spotting my mistake)

 

Workaround for resolve.aspx error Edit

First, find resolve.aspx, close.aspx and activate.aspx. they should be in your sharepoint 12 folder under \template\features\bugtrackingmodules\

open each in turn and find the two blocks of code in each file which do a resource load:

text="<%$Resources:tsa,ResolveBugPageTitle%>"

replace these with a hardcoded string, such as

text="Resolve Bug"

save the files. reload.

(thanks Jason)