Did you grab the latest version? I'm a bit surprised that it whiped the drive. Unless you tell it otherwise, Ubuntu will resize the Windows disk to fit Ubuntu, then add an entry for Windows in the boot menu, so you can dual-boot (If you resize manually, it will still do so, that's how I setup my computers).
There are two ways to check if the ntfs partition is still live, use the program gparted. It's pretty easy to understand it, open it up and see if you can locate the partition.
Other way is to open up a terminal (Applications>Accessories>Terminal) and type sudo fdisk -l
It will ask for the user password (The account needs to be in the sudo group, the first user created for the system is in this group by default), type it in and it will spit out the partition table for the system.
This is an example of one of my disks if I were to use the fdisk -l command:
Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xf52bcf0e
Device Boot Start End Blocks Id System
/dev/sdb1 * 1 66 530113+ 83 Linux
/dev/sdb2 67 12284 98141085 83 Linux
/dev/sdb3 19154 19457 2441880 82 Linux swap / Solaris
/dev/sdb4 12285 19153 55175242+ 7 HPFS/NTFS
I have my partitions set up a little different then the standard. Basically what you are looking at, is the first partition is ~500MB, this is my /boot partition.
The Second partition is ~98GB, which is the Root partition. Then we have the swap partition, which is ~2GB.
Finally, there is the NTFS partition, which would hold the windows install (I actually fibbed that partition table, windows is on a separate disk :p)