http://www.arm.linux.org.uk/ will take you to Russell King's main ARMLinux site which is the definitive source for current ARMLinux kernel updates, ARM architecture information and general info.
Aleph ARMLinux updates including new packages not yet available from Debian's standard distribution are available from ftp://www.armlinux.org/debian/. You should add this to your /etc/apt/sources.list file so that the latest updates will automatically be obtained when you do apt-get upgrade.