The short answer is: yes.
Best is to boot using a xUbuntu live filesystem, and perform all partition information changes.
Check the following partition.

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2550    20482843+   7  HPFS/NTFS
/dev/sda2            2551        3766     9767520   83  Linux
/dev/sda3            3767        4028     2104515   82  Linux swap / Solaris
/dev/sda4            4029       24322   163006074    f  W95 Ext'd (LBA)
/dev/sda5            4029        7296    26250178+  83  Linux
/dev/sda6            7297       14591    58593750+  83  Linux
/dev/sda7           14591       24322    78162050+  83  Linux

Now - I want to add another OS - in my case - Mac OS-X. So - in case you want to add the hfs+ filesystem partition between sda1 and sda2 - you have to move all partition bigger 1 to partition + 1. this would result in the following:

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2550    20482843+   7  HPFS/NTFS
/dev/sda2            2551        7415    39078112+  af  Unknown
/dev/sda3            7416       10000    20764012+  83  Linux
/dev/sda4           10001       24321   115033432+   5  Extended
/dev/sda5           10001       10262     2104452   82  Linux swap / Solaris
/dev/sda6           10263       13041    22322286   83  Linux
/dev/sda7           13042       19121    48837568+  83  Linux
/dev/sda8           19122       24321    41768968+  83  Linux

Now - to be able to boot up the move OS - you will need to modify 1 file, and recreate the initrd file. For this - check the uid of the swap partition with:

$ sudo blkid  | grep swap
/dev/sda5: TYPE="swap" UUID="0bb117bb-d03e-4674-99ef-97a3575ed8f1"

Check that the UUID in /etc/initramfs-tools/conf.d/resum matches the UUID just discovered. If not - change it.
After that - recreate the initrd file with:

sudo update-initramfs -c -k 2.6.24-19-generic

Make also sure that the parition UUID's as found in the /etc/fstab match the new real ones.
And you should be able to boot again normally.