While Intel had wanted to release X Server 1.6.0 by the end of 2008, its release did not end up happening until late February when it brought DRI2, RandR 1.3, and numerous other features. This afternoon though, Red Hat's Adam Jackson has released X Server 1.6.1, which packs a couple of bug-fixes atop the X Server 1.6.0 code-base.
X Server 1.6.1 has a few fixes for SELinux usage, RandR, GLX, X Input, XKB, and Xext. In total there are 15 changes for X Server 1.6.1.
The release announcement concerning X Server 1.6.1 can be read on the X.Org mailing list.