Oracle is offering a free, beta version of its XE database product. The "Express Edition" is available as a free download for developers and students to play around with. But software vendors can also distribute it.
Oracle says it is based on the same Release 2 code base and is fully-compatible with other Oracle databases. It runs on 32-bit Windows or Linux. Red Hat and Novell will distribute the database.
Although the database is not an open source application the move is being seen as a counter to the threat from open source databases like mySQL.
More details, and download link, here.®