By default the registration page should be created with a $insertGoTo variable. This variable should be set to the login page. Here is what this line of code looks like on my pages:
$insertGoTo = "users_LogIn.php";
If you don't have this then you can edit the Insert Record server behavior and set the page for the 'After inserting, go to:' value. If you have any further problems with this please post back with the pages in question in a zip archive.