Module development and code questions

I'm just getting started developing modules, and I have a question about a good one to use as an example.

I want to build a document repository, where admin users can upload documents, categorize them, etc.

The mod-development handbook is great to gain an understanding of hooks, but I'd like to see a good example of a module that already has a complex edit state for its administration.

Can someone point me to a well-coded example that perhaps they used when writing their first comnplex module?

Thanks!

I was trying to find out what forum a particular node belongs to using sth. like this:

$nid = x; // the node to look for
$term = db_fetch_object(db_query('SELECT tid FROM {forum} WHERE nid = %d', $nid));
echo 'node:'.$nid.' belongs to forum:'.$term->tid;

The code works perfectly for me. But a user reported that on his install
the column 'tid' in table 'forum' is always 0 and therefore above code
doesnt work for him.

Any ideas on that?

I've been asking a bunch of questions tonight, its late so I think maybe that makes it ok... ?

I would like to mess with the format of the aggregator blocks a little bit. I don't like the traditional "more" link that lives at the bottom of feeds and it seems like a reduntant thing to me when the title of the block itself is a good candidate for a link to what we know of as "more".

I defined a mymodule_user function with just print(serialize($user)) inside.

function mymodule_user($op, &$edit, &$user, $category = NULL){
  print( "<h1>".serialize($user)."</h1>" );
}

But it is not invoked on user login (no output on page). The output appears
only when I click on user account link.
What I actually want to do is redirect after logih, with redirection URL based on user ID.
Please help.

Basically I want some blocks to be seen on both their taxonomy page, say taxonomy/term/5, and also on their page type, say type "agent." Right now to get this done I have to create 2 blocks. Are there any modules or hacks that extend the visibility options of blocks?

Thanks.

I suppose this will be pretty easy. I need a PHP block I guess that pulls nodes from taxonomy "agent" and orders them alphabetically. One more wrinkle, the Title is actually the agent's full name, it would be nice if I could sort by his last name. I don't know if there's an easy way to do that in the SQL. I'd like to do it this way instead of having a menu where I manually have to add names and sort them with weight (we all know that's a beating).

Thanks for the help.