Does anyone know of a website or resource to learn about important files / directory structures or data within the iPhone?
Soon i'll be learning to develop iPhone applications and I want to know everything about its internals, if anyone knows a resourse that would be great.
What I want to do is.
How to access the database. Where system settings are stored. How to gain access to the Mobile Comm Server
etc...
All the information you'll need is available from Apple in their developer site.
File structure and other internals matter less than you'd think, as your app won't be able to get outside its sandboxed resources (unless you're writing jailbroken apps).
You keep mentioning database. What database are you talking about? In your last question about gaining access to a database, I assumed it was a database that you had as part of your app. The iPhone OS probably has many databases, including the Contacts database, the songs database, the album photos database, etc. There are some limited ways to access this data, but they're on Apple's terms and I have to emphasize the word "limited".
As a previous respondent said, the best place to start is at Apple's iPhone Dev Center, but you won't find anything on jailbroken phones, accessing any of the cell or communication systems, nor the system settings, among many other things.