what is BeagleBone

http://beagleboard.org/Products/BeagleBone

System Reference Mannual

https://github.com/CircuitCo/BeagleBone-RevA6/blob/master/BeagleBone_SRM_A6_0_1.pdf?raw=true

Getting Started

http://beagleboard.org/Getting%20Started
Note: Additional FTDI USB to serial/JTAG information and drivers are available fromhttp://www.ftdichip.com/Drivers/VCP.htm

Update to last image
Get lastest sd card image
http://beagleboard.org/latest-images/
Clone lastest images to SD card(at least 4G SD card)
http://downloads.angstrom-distribution.org/demo/beaglebone/

  $ sudo -s
   (type in your password)
  $ zcat Angstrom-Cloud9-IDE-eglibc-ipk-v2011.10-core-beaglebone-r0.img.gz > /dev/sdX
  $ exit

Build the beaglebone

Dependencies

http://www.openembedded.org/wiki/OEandYourDistro#Mandatory_packages

sudo apt-get install sed wget cvs subversion git-core coreutils \
    unzip texi2html texinfo docbook-utils \
   gawk python-pysqlite2 diffstat help2man make gcc build-essential g++ \
   desktop-file-utils chrpath 

Build

http://downloads.angstrom-distribution.org/demo/beaglebone/

git clone git://github.com/Angstrom-distribution/setup-scripts.git
cd setup-scripts
./oebb.sh config beaglebone
MACHINE=beaglebone ./oebb.sh bitbake systemd-image

If you want other images, you can check the following folder:
peter@peter-VirtualBox:setup-scripts$ ls sources/meta-angstrom/recipes-images/angstrom/
console-base-image.bb  development-gnome-image.bb  hardware-bringup-image.bb  systemd-image.bb
console-image.bb       efl-nodm-image.bb           systemd-gnome-image.bb     xfce-nm-image.bb

Unpack to SD card

After building, MLO, u-boot.img, uImage, rootfs can be found under following folder:
build/tmp-angstrom_v2012_12-eglibc/deploy/images/beaglebone/
SD card should be 2 partitions:
1st partition is in VFAT format
2nd partition is in EXT4 format
You can create these 2 partitions by the tools you prefer.
Or use this script
http://downloads.angstrom-distribution.org/demo/beaglebone/mkcard.txt
/bin/bash mkcard.txt /dev/sdX

copy MLO, u-boot.img to 1st partition
unzip rootfs to 2nd partition
suppose you have mounted 2nd partition to /mnt/rootfs

sudo tar -xzf Angstrom-systemd-image-eglibc-ipk-v2012.12-beaglebone.rootfs.tar.gz -C /mnt/rootfs

Enjoy your beaglebone.

Reference

http://beagleboard.org/Products/BeagleBone
http://circuitco.com/support/index.php?title=BeagleBone
http://downloads.angstrom-distribution.org/demo/beaglebone/