GRASS 4.2 has been superceeded by GRASS 4.3 (a derivitave of GRASS 4.2.1). Please refer to GRASS 4.2.1 or GRASS 4.3 for information.
Download GRASS 4.2.1 (current)
Download GRASS 4.2 original (outdated...only get this if you want to reinvent the wheel)
Resourses: