I unfortunately don't have time to find an exact reference, but PHP has something called cURL - which can do a variety of things, but Im sure it can post vars to a URL and because it doesn't require actual navigation to that URL, you could catch your form inputs and then just do two (or more) cURL requests...
Check out the php.net manual, or just google 'php cURL post'
Post data sent via form is essentially html-driven through http header. I can't imaging that sending data from a php form page to an asp page would be a problem.
THis is where I'm getting confused. Are you saying that you've got both php and asp pages on your localhost server? I can't see that working, but perhaps that's just me. The local file would have to do the processing to send the data to the remote file (on remote server). ARe you sure you're looking for a php solution or do you need an asp solution?
Can't see the problem then. Just post the form to the asp page. You can post forms to other domains. You can send post data locally which can then send a form to your asp page by programmatically (js) clicking a form button on a hidden form. few ways to do it.
Your local receive page will be the crucial element.
You can populate the a form on the receive page and programmatically send that second form to the remote:
document.forms['formname'].elements['send2'].click() //or perhaps the
document.forms['formname'].submit(); //would work
..form.. filled with $_POST data from the first form...
<input name="send2" id="send2" type="submit" />
Listen nic, I'm sure there must be a much easier way of doing this, but I can't think of it. Anybody else?
OK, I think I got a solution for you, along the lines I mentioned. Here's a mockup:
Page1 (local) PHP OR ASP OR HTML
<form method="post" name="try1" id="try1" action="receive1.php">
<input name="data" id="data" value="any old text here" />
<input type="submit" name="send" id="send" value="Send" />
Receiver (local) PHP
...(do any server side processing you need, e.g. error checking etc)...
<form method="post" name="try2" id="try2" action="http://www.example.com/handler.asp">
<input name="data2" id="data2" value="<?php echo $_POST['data'];?>" />
Receiver (remote) ASP
I don't do ASP, but the $_POST equivalent for the 'data2' field can be picked up here.