Not at this point in time. But this type of 3rd party support will be added in the future;
In controller software release 5.2 or later, Cisco lightweight access points use the IETF standard Control and Provisioning of Wireless Access Points protocol (CAPWAP) in order to communicate between the controller and other lightweight access points on the network. Controller software releases prior to 5.2 use the Lightweight Access Point Protocol (LWAPP) for these communications.
CAPWAP, which is based on LWAPP, is a standard, interoperable protocol that enables a controller to manage a collection of wireless access points. CAPWAP is being implemented in controller software release 5.2 for these reasons:
To provide an upgrade path from Cisco products that use LWAPP to next-generation Cisco products that use CAPWAP
To manage RFID readers and similar devices
***To enable controllers to interoperate with third-party access points in the future
LWAPP-enabled access points can discover and join a CAPWAP controller, and conversion to a CAPWAP controller is seamless. For example, the controller discovery process and the firmware downloading process when you use CAPWAP are the same as when you use LWAPP. The one exception is for Layer 2 deployments, which are not supported by CAPWAP.
I serious doubt you will see any cross vendor mix of access points anytime soon with any of the big wireless players. There is to much money at risk ....
"Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin