Displaying data on the Web w/o ethernet shield

I have projects laying around which gives out data via arduino, one of them is temperature data logging and showing it in screen (via Processing)

Now I want to know, how can I make a system that would send this data to the Internet so that I can log into a website (or ip) and see that data and if necessary make changes (input to Arduino from the internet). I know this isn't possible without a webserver but I have a Raspberry Pi to act as webserver.

What I would like to know what is the process flow as I don't know any back end programming lang like PHP etc. How can I achieve this project, what will be the requirement ? How do I proceed ? I will be glad if a detailed description is given out by someone.

Thank You