Yes. Here are two ways to do it:
1. Use Disk Utility to partition the drive. Use the MBR format so Windows can boot from the disk. Create two partitions, one NTFS for Windows, and one HFS+ for your Mac stuff. Then install Windows.
2. Use Windows Setup to partition the disk. Create a partition for Windows and install Windows on it. Leave space for the Mac partition. Then create a HFS+ partition using Disk Utility.