A couple of points here, Cypherus:
NTFS Compression is enabled on a per-drive basis. Select My Computer, Drive (x), Properties, then tick / untick the Compression Box to enable / disable compression for that drive.
With Compression enabled on a drive, you can then enable / disable compression on a per folder or file basis in the manner you describe.
Do bear in mind that a compressed drive that gets very full is a real pain to sort out - to move files off the drive they need to be uncompressed, and if there is insufficient space on the disk to uncompress them they can't be moved!
Finally, there is a significant difference between NTFS compression and Zip compression (be it Windows or WinZip). If anyone wants to know more, just use Windows XP Help and search for "File Compression".
SD