Simple Private Area with static username and password

Hi,
I'm asking you the best way for make a simple LOGIN and LOGOUT to a private area with static USERNAME and PASSWORD (It mean I don't need to create a user but only check if the two values inserted in the login area is correctly).

There's some snippet for do that or I must code my own?

I'm sorry for my english but I hope you've understand my question

Thank's in advance,
regards

Davide

maybe
http://modx.com/extras/package/pagelocker

Thank's a lot!
I must try but this is a solution!

This solution need the login inside the private page,
but I want have a login form in all pages with action in the private page.

Thank's a lot,

Davide