Hi Ahmed,
Here is some info to get you started with this Upgrade process;
Q. I plan to upgrade my WiSM to the latest software version. Is there any recommended procedure to upgrade the WiSM?
A. A WiSM upgrade follows the same procedure involved in the upgrade of a 4400 Series Controller. Since a single WiSM module contains two 4400 controllers in it, you need to individually upgrade both WiSM controllers.
From this good Q & A doc;
http://www.cisco.com/en/US/products/hw/switches/ps708/products_qanda_item09186a00806e39b7.shtml#upgrade
Wireless LAN Controller (WLC) Software Upgrade to Versions 3.2, 4.0, and 4.1
http://www.cisco.com/en/US/tech/tk722/tk809/technologies_configuration_example09186a00805f381f.shtml
Here is the link to the Downloads Page (need CCO Login);
http://tools.cisco.com/support/downloads/go/Model.x?mdfid=280103774&mdfLevel=Interface/Module&treeName=Wireless&modelName=Cisco%20Catalyst%206500%20Series%20Wireless%20Services%20Module%20(WiSM)&treeMdfId=278875243
Hope this helps!
Rob
