Yes there are. There is a whole framework that my team designed and implemented for Solaris 10 that provides access to hardware and software crypto.
You can find out more about it at the following places:
http://opensolaris.org/os/project/crypto/
email to crypto-discuss@opensolaris.org
We will also be adding a kernel developer section to the existing chapters in the Solaris Security developer guide that covers the cryptographic framework: http://docs.sun.com/app/docs/doc/816-4863/6mb20lvgm?a=view
For now thought that book only covers userland.
We would be very interested in helping you out and I would love to know what you intend to use AES for in the kernel.