Arduino upload Data to server

Let's say i have a webserver from whatever hosting website service that supports php, and i want my arduino to send a number for example and for it to be displayed in the page, how do i do this?

I know there are some tutorials, but most of them barely explain anything and i want to know what i'm doing, and i prefer to know how to send a simple var and then go from there. So is there any basic sketch and php script ?

Also, where can i find documentation for these type of problems?

Thanks in advance

edit: forgot to mention i have arduino uno + ethernet shield

PHP+SQL +request

There are a number of ways to accomplish this task. One way is to have your Arduino script execute a POST request (see "Arduino post data to web page" on Google) to a PHP script that reads the POST request and then stores the new data in a text file or MySQL table. Then a second PHP script would retrieve the data and insert it as appropriate in a web page. Cheers.