TubeKit is a toolkit for creating YouTube crawlers. It allows one to build one's own crawler that can crawl YouTube based on a set of seed queries and collect up to 17 different attributes.
Ex-Crawler is divided into 3 subprojects (Crawler Daemon, distributed gui Client, (web) search engine) which together provide a flexible and powerful search engine supporting distributed computing. More informations: http://ex-crawler.sourceforge.net