mass republish your posts using oik-batchmove WordPress plugin

If you want to republish a set of posts then you should find the latest version of the oik-batchmove plugin fairly useful. You can now set a new publication date as an offset from the original publication date. e.g If you want to republish posts that were originally published in February 2007 as February 2012 then you apply a Date adjustment of +5 years when using the Republish post action.