Yes, you can. It's easier to do if you have two drives, one for each OS, but you can do it almost as easily with one.
In my experience, partitioning using a Linux installer CD can be a hit or miss. Usually, it's a miss, because without proprietary knowledge or drivers, it's difficult to manipulate NTFS partitions. I recommend PartitionMagic, which is the best partitioning software I've used. Just make a new partition on your hard drive, and make it at least 5GB, preferably more. You don't need to format the partition to any particular filesystem. Then, boot the installer CD, and select the new, empty partition, being careful not to select the destructive (lossy data) options. From there, you're pretty much set. Most Linux users agree that you need at least two partitions for Linux, one for the main filesystem, and one for swap (cache) space, which should be between 1-2x as large as your hardware RAM. Other partitions are optional.