If you are cool, you'll have a shell account somewhere. (If you are really cool you'll have UNIX running on your own computer.) Anyway, this is a better alternative to using your Mac because if you nuke somebody through telnet, it doesn't tie up your computer. (You can even write a shell script to do it again and again and again, but I won't show you that...)
Okay, using Fetch (My FTP prog of choice), upload "winnuke.c" to your directory. Now, telnet to your shell. Once you are in, type:
% cc -o nuke winnuke.c
% = The C-shell prompt.
cc = The command to compile.
-o = Means "Name the program <name that follows"
nuke = What we named our program.
winnuke.c = What we compiled.
NOTE: This program is only guaranteed to work on BSD, Linux and SunOS.
Now, to execute it, type:
% ./nuke microsoft.com
NOTE: "./nuke" is 1 word. This is how you execute a custom program in UNIX. ANOTHER NOTE: I'm actually not sure about the dot-slash thing. I only have experience with BSD, so I'm not sure if the Linux/SunOS command is different.