The archive-crawler project is building Heritrix: a flexible, extensible, robust, and scalable web crawler capable of fetching, archiving, and analyzing the full diversity and breadth of internet-accesible content.
Arc (http://arc.cs.odu.edu) is the first federated search service based on the OAI-PMH protocol. It includes a harvester which can harvests OAI-PMH 1.x and OAI-PMH 2.0 compliant repositories, a basic search engine which is based on database and an OAI-PMH