Accept Cookies in your iPhone browser to login to the mobile site
Cookies are required to remember your password.
From your iPhone go to Settings.
In Settings, go to Safari.
Make sure JAVA SCRIPT is "ON" and ACCEPT COOKIES is "From Visited" or "Always".
Reboot your iPhone for the Settings modifications to go into effect.
Press and hold the Home button and the top Lock button for 10 seconds to do a reboot.