Intel's ability to deliver a quad-core part before AMD may be due in part to differences between the two implementations. AMD's "K8L" will bring a native quad-core design with shared L3 cache, a new version of HyperTransport, and some significant architectural changes over the previous generation. Meanwhile, Intel's Kentsfield and Clovertown are simply made up of two Conroe or Woodcrest dies situated together on a single package, respectively.
AMD may therefore end up late on the quad-core front, but it does have its 4x4 enthusiast platform in the pipeline. 4x4 will allow users to install a pair of dual-core Athlon 64 FX processors into a single machine, which could provide some competition to Kentsfield on the desktop if AMD prices it competitively. We'll have to see how AMD handles the fight with Clovertown on the server front, though.