El PHP es lo que no se!
Código HTML:
<form method="post" action="contact-post.html">
<div class="to">
<input type="text" class="text" value="Nombre" onfocus="this.value = '';" onblur="if (this.value == '') {this.value = 'Name';}">
<input type="text" class="text" value="Correo" onfocus="this.value = '';" onblur="if (this.value == '') {this.value = 'Email';}" style="margin-left:20px">
<input type="text" class="text" value="Asunto" onfocus="this.value = '';" onblur="if (this.value == '') {this.value = 'Subject';}" style="margin-left:20px">
</div>
<div class="contact_bottom-textarea">
<textarea value="Message" onfocus="this.value = '';" onblur="if (this.value == '') {this.value = 'Message';}">Correo</textarea>
</div>
<div class="form-submit1">
<input name="submit" type="submit" id="submit" value="Enviar correo"><br>
<p class="m_msg">Asegurese que ha introducido una dirección correcta</p>
</div>
<div class="clear"></div>
</form>