Resize Linux Partition on Raspberry PI

Actually you can resize the disk while active in arch linux. might work for ubuntu, raspbian, debian and other linux based ones

As root:

• fdisk /dev/mmcblk0

Delete the second partition /dev/mmcblk0p2

• d
• 2

Create a new primary partition and use default sizes prompted. This will then create a partiton that fills the disk

• n
• p
• 2
• enter
• enter

Save and exit fdisk:

• w

Now reboot. Once rebooted:
resize2fs /dev/mmcblk0p2

Your main / partition should be the full size of the disk now.

another method with parted
http://elinux.org/RPi_Resize_Flash_Partitions

sources: http://archlinuxarm.org/forum/viewtopic.php?f=31&t=3119