I don't believe the link was active until the official announcement at 9:30am PST, but it is now. Java.net is the principal site for the Java open source community and the OpenJDK. You can download an early build of the Java SE 7 HotSpot JVM, the javac compiler, and JavaHelp in the new OpenJDK project. These are the first parts of the Java to be open sourced. Like OpenSolaris, the rest will be released over time.
Oh, and if you're curious as to why release Java under GPL and not another license, including Sun's own CDDL - check out this article for an explanation.