Module development and code questions

Hello again and sorry about my poor english.

I would like to insert a custom content (text) under the view of a node. I know that it is possible putting something in theme file (node.tpl or so). But my question is:

It is possible to extend the hook view of a node witouth hacking it or touching theme files?
I would like to do something like this:

mimodule_extend(node_view) {

blablablacodecodecode

}

I am searching thru drupaldocs but no luck.

Thanks in advance

from this doc page:
http://drupaldocs.org/api/head/function/hook_nodeapi
I am trying to find out when the node actually gets written into the db. ( i need the value of 'nid' ) Is it saved during the 'fields' operation, or during the 'insert' operation? when can i find out the value of the freshly inserted node id, to use as a key in my auxillary node data table?

Hi, I've just got Eclipse going. I've downloaded what I think is the HEAD, but it's not entirely clear.

The top of the changelog file says:
drupal x.x.x, xxxx-xx-xx (development version)

Does that mean this is the HEAD version?

How do I make the menu for SimpleNews settings invsibile to users?

Sorry about my poor english...

I am trying to add a custom field to a page node. I know that it is possible to define custom nodes using flexinode, but I do not want to use this module. I only need one more field in the default node.

I think that I would create or extend de database in order to store this field, and I would need to extend the page module.

It is possible?

Thanks in advance

Say that I want to create user groups where each class is its own user group. And I each want them to view their own data but not somebody elses. How would I accomplish that? I want each class to read its own announcements, its own forum data, etc etc. Is there something I can do with taxonomy to make that happen? I don't really want to have to build custom modules for everything or hack a bunch of modules to get this accomplished.

Thanks!

Jay