Automatically update twitter & facebook from html form using php

Hi, I have a html text area on a page in my admin system, the field is called social. what i want is a piece of code which will pick up the variable in php and then post the contents of the variable to twitter and facebook. I know the dk can be downloaded to do this and so anybody who has done it before will more than likely have the code and so i do not really expect to pay more than £50 GBP as the source code for this is already available online.