Plugin display form, where user can choose how many posts should be display per page. Choosen value is stored in cookie.
This plugin can be quite useful, when you want to let users to decide how many posts they want to see per page. You can see how it works on this page http://plugins.dickiebirds.com On the top of page there is a simple form - please try it before first use ;-)
At the admin panel - 'Settings->DB Posts per page' you can set up label and submit button text. You can choose between simply text box or dropbox on user side too. If you choose dropbox, when user select from the dropdown the page can automatically reloads with the chosen posts per page.