Thought the paper on [link|http://www.theserverside.com/news/thread.tss?thread_id=30067|Features, strengths, and weaknesses comparison between Microsoft SQL Server 2005 (Yukon) and Oracle 10g databases] might be of interest to some.
And while I'm linking to articles, might as well throw in [link|http://www.onlamp.com/pub/a/onlamp/2004/11/18/slony.html|Slony for PostgreSQL] a database replicator project.