on a site, i have a contact form, which emails their input to me, and an auto responder sends them an email back.
The message goes as follows

$EmailContentText_2 = "This is an automated response, just to let you know that your request for a proposal is on its way to a real human being. \n\nBecause we carefull......";

How do I format the text to 1. parts of the message be italics. 2. insert a hyperlink. It seems i can't do any html tags within it.

There a way around this?

Actually, you can put HTML tags in your message, only it won't result in a MIME-compliant (i.e. correct) email. It will result in something most email clients will refuse to parse.

The easiest way for you to see how HTML should be embedded in an email message, is to fire up an HTML-enabled mail client, compose the desired message and send it to yourself. Upon receipt, open the message and look at its source. Then simply use the source as a template, snipping all unneeded headers.

With all that having been said, I'd actually advise against embedding HTML into email messages. It'll look pretty in some clients, but with other clients it can be a hassle, and some don't even support it. Plain text never fails.