You need to SFTP into your iPod, and then drop it in /Applications. However, I believe there are some other config files that are strewn about.. you'd be better off using iJailbreak or something to jailbreak and install SSH, then install the iPhone apps with that.
thanks for the reply. I managed to sftp the wearther app over but its not displaying on the ipod. I gave up last night but will give it another go tonight.
Just to clarify. I copied over the Weather.app folder and in there is another folder called Weather is that correct?