Description of problem:
Update to 2.6.41.1-1.fc15 kernel headers omits amd_iommu.h, which is needed for virtualbox, and presumably other modules as well. 

Version-Release number of selected component (if applicable):
2.6.41.1-1.fc15

How reproducible:
100% (4 machines so far)

Steps to Reproduce:
1. Update to 2.6.41.1-1.fc15 kernel
2. Attempt to recompile virtualbox kernel modules (of course also fails dkms)
3.
  
Actual results:
Kernel modules fail to compile

Expected results:
Kernel modules compile

As noted in the link below, copying the header from 2.6.40.6-0.fc15.x86_64 (or as appropriate) fixes the problem.

Additional info:
I have personally tested this only on 64-bit installations (four very different machines), but there are reports also for 32-bit kernel - see e.g. https://forums.virtualbox.org/viewtopic.php?f=7&t=46216