Yes, it's absolutely possible.
This is how you do it (for safety do a backup before following the instructions, in case something go wrong);
First make sure you boot Windows, then download your iso if you haven't already. Afterwards download https://sourceforge.net/projects/partedmagic/files/partedmagic/Parted%20Magic%205.5/pmagic-5.5.iso.zip/download
and lastly http://unetbootin.sourceforge.net/
Now, run the Unetbootin installer. Choose your Parted Magic iso and choose frugal install.
Install it to your windows partition (normally C:) when it tells you it's done you can reboot.
When you reboot into your unetbootin installation you should be able to choose to load Parted Magic entirely into RAM. This means that, once running, it will not actually be using the hard disk at all - leaving you free to resize the partitions.
Once Parted Magic has booted, select the gparted application. It's fairly easy to use. simply select your Windows partition, click edit, and shrink it by about 8Gb.
Make sure you leave the empty space to the right of the partition. Then click apply.
Unetbootin may prompt you to remove the installation. If not running the unetbootin installer again should remove it. (If neither happens then control panel and add/ remove programs on XP or Programs and features on vista/7 and remove it there).
Run the Unetbootin installer again and this time, select your Ubuntu iso to use for the frugal install. Reboot into this new installation. Once in Ubuntu, run gparted.
In the spare space create a new partition, and format it as ext4 (often you'll be told to create a swap partition; you can if you want; I don't normally; google will tell you more). Click the install icon on the desktop. When it gets to partitioning, click specify manually. Choose your new partition and pick use as: ext4, mount point: / Let the installer do its job. now you have a choice. Left like this the system will allow you to dual-boot (i.e. choose between Ubuntu and Windows when you switch on the pc).
Reinstall Parted Magic as we did in step 1. Reboot to parted magic (loading it to RAM again). Open up gparted, move the Ubuntu partition to the left, then grow it to the right. Do not try to grow it to the left. (This is the time to create your swap partition if you want one). Now reboot. You have now installed Ubuntu alongside Windows without even touching a disc or usb! :)
The source: http://community.linuxmint.com/tutorial/view/171