How can I make iframes & modules hidden to guest

[Guest]

I have my chatbox set up on my forum as an iframe. when guest visit my site, all they see is big black space where the chatbox is located that says "you must be connected to use the chatbox". I want to remove this by making the iframe only visible to members and not guest.

I also want to create some modules that are only visible to members and not guest, or only to guest and not members, such as a welcoming image on my homepage that should be visible only to guest, and disappear/become hidden to members.

**EDIT- Here is what my chatbox looks like to guest and this is why I want to make this hidden to guest so they dont see this and get annoyed:



That entire black rectangle is what guest see under the navigation bar on every page of the site.
Check it out yourselves, my site is http://electronicnetwork.all-up.com

This can get annoying for people visiting the site. This is why I really want to learn how to fix this

[Guest]

??

[Guest]

bump - this is something i been trying to figure out still.. is there a code to make an announcement appear for members only?