I'll be heading to Prague for the Apache Lucene Eurocon in May where I'll be speaking. Should be a great conference. Hard core developers can get training on Solr and Lucene. The conference is sponsored by Lucid Imagination which offers commercial subscriptions for companies using these technologies.
I'll be speaking on how open source software, cloud computing and big data are disrupting the traditional software industry as we know it today. (For related info, check out David Fishman's excellent blog posting: Data Disrupted.) Prague is a great city and it should be a fun time.