Inside the framework represented by Data Providers and Service Providers OAI-PMH compliants, Portal systems play (no doubt) a significant and crucial role as far as single access point to "open literature" and users' environment personalization issues are concerned. This presentation shows the joint CASPUR-CILEA activity which led to the development of a portal named PLEIADI (portal for Italian electronic scientific literature on open archives and institutional repositories), name also assigned to a similar project devoted to dissemination of open-archives culture in Italy. Service Provider VS Portal relationship is shown as well, focussing on open archives search facilities made available through the Portal system. Last a first PLEIADI prototype developed with an open source software called XOOPS (eXtended Object Oriented Portal Software) is presented.