It seems like Lion supports NTFS (by plugging in a USB Flash drive which is NTFS). So for hard drives such as the WD Passport or Toshiba 1TB, which are made for the PC (running Windows XP/Vista/7), they can be used on the Mac running Mac OS X Lion as well?
1) They are not "made for" PCs, they may simply come pre-formatted. If they are USB, they will almost certainly work with any OS known to man that supports USB
2) NTFS support is read only, you cannot write (without 3rd party software) but you can format as Fat 32 or EXFAT etc and have the drive be read/write by almost any OS including Windows/Mac/Linux etc/
If you want to share the drive across Windows and OSX (so that both can see the same files) then the suggestions about FAT apply.
As well as the FAT problems there is loss of precision of timestamps, DST problems. In addition OSX will write a lot of stuff to the drive which is confusing to Windows.
If you do not need to share files you are better to format the drive as Mac OS Extended (Journaled) using Disk Manager