Display iPhone Screen on TV or Computer!!!!!!

does anybody know of an app or cable or device that i can use to display my iPhone screen on my TV or computer? I have both sets of Apples cables to connect to TVs, but they are only enabled when using as an iPod.

i want something like what is used to keynotes to view an iPhone screen on the external montior. There has to be a way because Apple displays the screens during keynotes, but it may not be one Apple wants the outside public to have. If you look at the keynote videos, there a big fat black cable that comes directly out of the iPhone.

i heard that it might be part of the iPhone developer tools. i am gong to get the SDK soon. so hopefully it is easy to do.

thanks in advance