This is a simple package that sends a redirect to another location, depending on its parameter settings. It is intended for the situation when you moved parts of your site to another location in order to reorganise your site, but don't want old links such as users bookmarks, links from remote sites, external search engine hits etc. to break.
Mount it at the old location using the openacs site-map, and set its NewURL parameter to the new location. E.g. when you moved a tree of your site from '/some/old/path/' to '/newurl/' then mount an instance of redirect at '/some/old/path/', and set its NewURL parameter to '/newurl/'.
The package is in file-storage: http://openacs.org/storage/file?file_id=118294
I would also suggest to set the core flag to true so that it gets installed upon OpenACS installation, since it serves a general purpose that might as well be implemented in the site-map/request-processor if it wouldn't be easier like that as a package, and it is fairly lightweight (no datamodel, few files).