First saw this last night on TechCrunch. By now the news has probably spread all over the Net :)
Yes, its true - Sun is buying MySQL for $1 billion.
Here's the official post about it from Sun Microsystems CEO Jonathan Schwartz.
As lots of others have commented, including of course, Michael Arrington of TechCrunch and Sramana Mitra, among others, this is good news for customers in general and the open source movement in particular, and looks like a good fit for both companies.
My first reaction (confirmed a few hours later by reading the details in Jonathan's post above) were that Sun and MySQL can now optimize Solaris and the MySQL database to work for better performance, etc. - just as Oracle had done with Linux, starting a few years ago (though there was no acquisition involved there). Leveraging things like ZFS can probably improve MySQL response, scalability, etc. Jonathan's post mentions quite a few other ways in which he thinks all stakeholders (not just Sun, MySQL, and their customers, but also Sun's OEM partners) will benefit. Of course it depends on how well they execute on the intended goals.
[ Make sure to read the post about "OEM partners" above - a pretty interesting one by Jonathan again. I love this sentence of his from that post:
"As I said to a journalist today after the announcement, vendors that don't offer choice can only serve customers that don't want choice... while IBM and Sun can serve the rest."
P.S. The other news in Sramana's post above (titled "Today's Two Big Acquisitions"), is about
Oracle acquiring BEA Systems for $8.5 billion - which, though a much bigger sum, and may well be similarly synergistic, is not potentially as game-changing as the Sun acquisition, at least IMO ...