Hi.
Here comes a temporary solution on hiding input fields of Contact Form 7 plugin after input data is sent.
You may see some replies on this subject on http://wordpress.org/support/topic/244959, but the hacks mentioned are not working for version 2.2.1 of this plugin.
So, if you want to hide all input fields including submit button after data sent success:
1) Go to "includes" folder of plugin and edit the "classes.php" file.
Add the following line right after $class .= ' wpcf7-mail-sent-ok';
echo "<style type=\"text/css\">.showhide {display: none;}</style>";
2) In the admin panel of contact form 7 plugin, add the following line in the beginning of the forms description: <div class="showhide">
Then close this tag in the end of the forms description: </div>.
Just for example:
<div class="showhide">
<p>Your name
[text* your-name] </p>
<p>[submit "Submit"]</p>
</div>