try this code:

//OPTIONS
$sendTo = 'email@ofadmin.com'; //address to end form contants to
$subject = 'Enter you subject here'; //subject of the e-mail

//mail headers
$MAIL_HEADER =...

you shoud seek out a tutorial on writting PHP classes. this will help you a lot in the future. it's good practice in my opinion to write it once and reuse it forever. building up a library of classes...

try doing a search for "shout box" it's a simple realtime message posting thing-a-ma-jigg. if you need something more advance then just search around for opensource chat scripts