To use the NIfTI-1 Data Format Flash Help, unzip the 'NIfTI1DataFormat_FlashHelp.zip' to a new folder and doubleclick the 'The_NIfTI-1_Data_Format.htm' file. 
This will open the documentation with the appropriate menu.

For more information about the NIfTI-1 Data Format, please consult the NIfTI Data Format Working Group website at http://nifti.nimh.nih.gov/dfwg/ .

December 2004.