Yes, it changed yesterday.. They have apparently pulled off the v1 login screen and are now redirecting it to v3's... which is MUCH slower to load, alas, and not as nice as the old one...
I'll remove the old URL for next releases, in the mean time, to reduce the login screen rendering time (by avoiding the redirection), simply tick the "Use the new SL login screen" check box in "Preferences" -> "Cool features" -> "User Interface".