Hmmm,
Just fired up VS2008 to start a new Addin based project, but couldn't find my Pipeline builder addin anywhere on the tools menu! Argh!
Downloaded it again from the codeproject page:
http://www.codeplex.com/clraddins and ran the installer - chose 'Repair', restarted VS2008... Still not there! ARGH ARGH!
Tried disabling the addin via the 'Tools->Addin Manager' errr manager, but to no avail....
Finally - re-ran the installer, chose remove - removed the builder, reinstalled it and now thankfully it's back in play! Phew...