Although the project is hosted on GitHub, additional information and a changelog can be found on the Forums of Bukkit.
Just put the .jar file and the folder with the ignored-items.txt in your craftbukkit server's plugin folder and (re)start the server.
You can get the correct data values for the items from The Minecraft Wiki.
Make a newline-seperated list with only the id's (numbers) of the item you want to ban. Save the list as ignored-items.txt in a folder called BannedItems. The folder should be in the same folder of the .jar file.
The command can be used just the same way you would use the default /give command.
Alternately you can also use /g, /i or /item instead of /give
/give <PlayerName> <ItemId> <Amount (optional)>
The plugin currently supports a permission check by the key 'BannedItems.give'.