Module development and code questions

Has anybody made (started to make, considered making) a module (perhaps to compliment the project module) where users can log time spent on tasks? Just wondering! If I could roll back time like Hermione in Harry Potter III I'd have written it by now!

I know the weblink.module has been updated to Drupal v4.5, BUT it really does seem to me that it wasn’t reviewed before release.

Why do I say this?

Is there a way to list node types for which a user can perform an "update" operation?

The following is custom home page module. I want to call blog, story, quotes etc., in a menu.
By default all the blogs will be displayed, when a user clicks on story to display all the stories, similarly for quotes.
I went through the api and found that by calling blog_page the entire blogs posted will be displayed respectively for other nodes.

I am struck in calling the function menu, how to call the theme to display the output ?

php code ....

.... Implementation of hook_menu()....

I have a copy of the affiliates module used on http://spreadfirefox.com . It lets you create affiliate links with specific paths and banners for your site and provides a point system for tracking user success, also a block to display recent affiliates. I've been authorized to release it to the drupal community. It just needs an update for 4.5, but that may only require a few lines for node_access issues. Should be very simple for someone not as daft as me.

I'd like to modify the image.module. Simply when somebody clicks on the "original image" a new page layout should come up with the full size image in the middle. Can you give me pointers as to what needs to be changed in the image.module and how to include the full size image into a new page layout?