iPhone SDK build of default application fails

FROM : Edward Kenworthy
DATE : Sun Jun 15 20:32:17 2008

Hopefully someone can help me :)

I've just downloaded and installed the iPhone SDk, run up Xcode, File-
>New and created several of the template applications. In each case I 

click Build & Go... and nothing. The status bar says it's building but 
it spends forever building (doing nothing). (I've made no changes to 
the project at all).

Help!

Edward