krenshau wrote Thank you for that information. That is a very good resource. That site has helped me a lot. However, maybe I am a little dense in this situation. This statement from the site says, "The Portal administrator will ultimately decide which users actually have access to the control." This implies that I don't need to control view permissions in the module ( I am referring to the view control, not the link to the edit control). Is it safe for me to assume that what I am inferring from that statement is correct?

Yes. When the Portal administrator places your module on the page they can set the "View" permission. They indicate what users and groups can see the module. You don't have to do anything to make this work.

krenshau wrote Great! Thank you for saying that very concretely. That clears up everything for me.

Also see:

http://www.adefwebserver.com/DotNetNukeHELP/DNN4_ModuleDevelopersGuide/

for a better explination of how the security works.

Thanks for your sharing the great information! However in my situation, if I would like to dynamic load the module in our code, how  to deal with it? for example, if I set the module visibility to false, it will hidden.