Yes, it's possible. If the drive is formatted NTFS and you don't want to erase the drive, then you will need a third-party utility on your Mac to enable writing to an NTFS formatted drive from OS X. There are several solutions available such as:
If you are willing to format the drive, then you can partition and format it for OS X, then you can create one partition for the Mac and a second partition for Windows. Or you can format the entire drive for a Mac and use third-party software on Windows such as MediaFour's MacDrive.
If you decide to reformat the drive you will need to do this:
1. Boot from your OS X Installer Disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu.
If you are preparing an external or a non-startup drive, then open Disk Utility in your Utilities folder.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID (for Intel Macs) or APM (for PPC Macs) then click on the OK button. Click on the Partition button and wait until the process has completed.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.