AE3DTools announced the release of DarkCorner, an AE plugin that computes ambient occlusion interactively based on Z-depth information using the GPU.
As a bonus, DarkCorner comes with JaggyBuster, AE3DTools’ GPU anti-aliasing plugin for AE. A trial version of DarkCorner is available, and it also includes a demo of the JaggyBuster plugin (the later one is 64-bit only, for the moment). More at AE3DTools.