The front page does not use any portal package unfortunately. Last time I remember reading about it was a statement from Openforce that they would rewrite the new-portal package and make it usable for OpenACS. Anyone has updates on this?
What is used on openacs.org are custom written mini templates that are being included via the <include src=""> tag. You can check out the full source code of the openacs.org website, which is based on oacs-4-6, with this command:
cvs -z3 -d :pserver:mailto:anonymous@openacs.org:/cvsroot co openacs.org-dev
or browse the code here: http://dev.openacs.org:8000/cvs/
