The first public version of the org.eclipse EGit plug-in version 0.7.1 has been released at EclipseCon. EGit is based on the pure Java implementation JGit, which means that it has no external dependencies or native code requirements; something which has historically hindered the adoption of Eclipse's Subversion support.
As an incubating release, EGit is neither feature-complete nor bug-free; however, it is being released ahead of the Eclipse Helios release in Summer this year to gain feedback and to provide a 0.8 release in time for the Helios release train.
There is a User Guide available on the wiki, as is a introduction to DVCS for those that haven't used it before. More information can be found from the EGit project home page.
Git is the chosen future DVCS of Eclipse.org; bug 257706 contains the debate if you want to read further, but licensing issues were the key motivator behind that decision. Since migrating to Eclipse, the EGit code has been re-licensed as EPL, and the JGit code has been licensed under the EDL, which permits its reuse in other tools like NetBeans. Whilst there is still external support for Hg in the form of MercurialEclipse, the fact that the underlying Mercurial libraries are licensed under GPL means that it can't be distributed from Eclipse.org, which is the same problem that inhibits Subversion proliferation at Eclipse today.
Please send feedback by filing bug reports against EGit and/or the egit-dev mailing list.