How do i make my WD Passport Work on Both Windows and Mac

Before I use my WD external drive (Passport Essential 250 GB)  I saw that the file format on my PC is NTFS based.  I will be loaning my drive to my niece who has a Mac computer, will she need to download this  NTFS-3G application so that she can upload the pictures to my drive?  Her file will range from 50 to 80 GB… and I will need to be able to retrieve and upload the files from drive to my PC.