Jonas Hummelstrand's General Specialist announced Brendan Bolles' Multi-channel OpenEXR plug-ins (in Beta, with sample project), which "consist of a replacement OpenEXR plug-in, a 3D Channel plug-in (EXtractoR) for reading in any channels present in a multi-channel file, a regular 3D Channel plug-in (OrphExtract) that works in float, and an Object/Material ID plug-in (IDentifier)."
from the Readme: "OpenEXR has become the most commonly used file format in 3D computer graphics rendering. The format was created at Industrial Light in Magic with this specific purpose in mind. OpenEXR files store high dynamic range RGBA pixels in a 16-bit floating point format using lossless compression, but can hold an any number of image channels. Presently, After Effects doesn't include a way to read the extra image channels in an EXR file. These plug-ins have been created to fill that gap."
Brendan also includes a simpler version based on OrphEXR, which used to be available from The Orphanage. The plan is to make this package open source and freely available to the AE community, and include it with ILM's distribution of OpenEXR.