Post installation

In a different post, I was directed to look through some php snippets. I did and found something that I liked, but I am not a php guru at all. In fact, I know very little php. Here is the code I want to use in a block:

I was wondering is there a way I can make the drupal website membership by invitation only
is there a module or some settings that I can use to make this happen.

Is it possible to add a secundary tab to "user/*/edit" which links to massmailer list subscriptions?

Its all in the title really!!

I'm developing a site with the following book structure:

3D CONFERENCES
-London
---2006
-----Register
-----Programme
-----Location
---2005
---2004
-Paris
-Rome
-Florence
-Moscow

ARTS CONFERENCES
-London
---2006
-----Register
-----Programme
-----Location
---2005
---2004
-Paris
-Rome
-Florence
-Moscow

I want to know how can I display the banners using the banner module on top of the page can someone please help me in this

I want to know how can I display the banners using the banner module on top of the page can someone please help me in this