Status Updates

Hi and greetings to all.

I have been working with drupal for a small while, and I like the system so far as it has been relatively easy to integrate with an existing website, except to say there are some issues with having a consistent theme but besides that (I have settled on chameleon for users and admins) I'd like to know more about Status Updates in that when they are run manually, all I get is the following message:

Attempted to fetch information about all available new releases and updates.

Then there is nothing more.

It talks about cron, which is another thing I have been trying to understand, and when it asks I run it but not until that time so what I am asking is, is there a way to see which files may be available or what has changed?

I guess it may be a big ask to have information about every changed module available to you as part of what is dragged up by a "customer" site, but I really would appreciate it if there was something here.

Thanks and regards.