Get post values of form created by widget in sidebar

Your form needs to have method="post" and action="someScript.php" defined. It will send the post variables to wherever you deifine in your action=""

<form method="post" action="someScript.php" >
   <p>
     <label for="db_sub_name">Name</label>
     <input type="text" name="db_sub_name" id="db_sub_name" value="" placeholder="Enter your     Name">
   </p>
   <p>
     <label for="db_sub_name">Email</label>
     <input type="text" name="db_sub_email" id="db_sub_email" value="" placeholder="Enter your Email">
   </p>
   <p>
     <input style="float:right;" type="submit" />
   </p>
</form>