Sending $_POST-information without a form

Let’s say I have three files.
[LIST=1]
[]RegistrationForm.php
[
]Message.php
[*]DBAction.php
[/LIST]

The information is entered in a form in the first file. You press submit and you send the information to the second file. In this file you simply get a message saying “Thanks” or something.

Now, here is my quesion:
Can I somehow take the array of $_POST information from RegistrationForm.php in Message.php and transfer them to DBAction.php for the final database interaction.
I’m not doing anything like this, I just want to know if there is a way of transfering the $_POST-info from one file to another.

I know I could have used a form with hidden fields and just inserted all the info, but is there another way of doing it?