Phillipe Cand asked me recently where you should put your SSIS templates so that you can use them as the basis for your packages. The answer is:
%ProgramFiles%\Microsoft Visual Studio 8\Common7 \IDE\PrivateAssemblies\ProjectItems\DataTransformationProject\DataTransformationItems
Once you have them there you can right-click on a project in BIDS and select "New Item...". Your template should be available.
Any problems, let me know!
-Jamie