Do this, create a new folder for custom item templates, let's say it's:
c:\VS\Templates\Item
Now on VS go to Tools
-> Options
-> Projects and Solutions
and set the User item templates location:
option to the folder above, hit OK.
You will notice that inside c:\VS\Templates\Item
folder some folders will be created. What you have to do is to create a new Web
folder inside the Visual C#
folder that has been created automatically, therefore you'll have:
c:\VS\Templates\Item\Visual C#\Web
Drop the zip file with the item template there and the item will show up under the Web
category when you are creating new items. You can create other categories as well just by creating new folders under Visual C#
folder (or any other category folder for that matter).
Good luck.