Everything is through the login link in the top right of the index page.
I'm not sure if it would be my browser settings or not, but I just tried it again a few times in a row to different results each time. The first time the login button sent me right back to the main page without logging me in, the second time it sent me to
http://login.php again, and the next time it logged me in correctly. I'm running Chrome 9.0.597.107 on Windows 7 Ultimate 32-Bit with default settings. I may try with Chrome on Debian and see the results. It works correctly in every other browser for me.