Module development and code questions

The subject pretty much describes what I'd like to do. Any tips?

I want a node labeled something like "My account", which displays the sign in/sign up form if you're not already signed in.

If you are signed in, I want to run custom PHP code which will have access to the authenticated username/email address.

I'm looking at 2 different approaches (I'm a total newb) but not sure if either are right...

I've written a script that I'd like to have running on my site. I'm guessing to do this I would have to add it as a module and then enable it. Here is the code I tried using to get this to happen, which i modified from the j_query_interface module,

nta.module:

I've never seen anyone do this, but it seems reasonable to me: Is there a reason why variable defaults are not set in the install (or update) functions?

Is there a reason why so many people go to such lengths trying to make a README.txt look decent when text files are never going to look decent? We're working with a web development tool here, so we must all have browsers. So why not have the README files be HTML?

Hi, I've got this teaser view that displays the following fields as a list, one on each line. I'm trying to make it more compact -- so that the 3 fields are displayed on just 1 single line. Can anyone tell me how to do this?

I've defined a CCK node type that anybody can create.

But I want to check against the DB before I let someone create that kind of a node. Basically, I'd like to have a condition, which if not met, would stop the creation of the node.

Is there an appropriate hook for this? Also, is there any way of storing the draft node even if the condition is not met? Can I mark it as dormant or something?