I'm trying to use xcode to develop a website. Installed the cappuccino plugin but when I go to create a new project no web templates appear. Any idea why? I have version 4.2.1 installed on Lion 10.7.3
There is no plugin for Cappuccino (since XCode 4 does not allow for plugins).
If you're talking about XCodeCapp, it's actually a separate application that you run. You can learn more about how it works here: http://antoinemercadal.fr/xcodecappcocoa/
There was an old plugin a long time ago, but it's long deprecated and of course will no longer work with XCode since version 4 no longer allows plugins.