I have recently downloaded installer.app directly to my iPhone, bypassing my PC. I have also downloaded some themes to my PC's desktop and would like to add them to my iPhone.
What is the process I need to follow to take them from my desktop in zip format to my iPhone?
Ok, so you have installer running on your phone right? You'll have to use that to install summerboard and/or customize. These 2 programs allow you to change different aspects of the phones visual interface. Once you do that you can use either SSH or iBrickr to transfer the themes on your pc (after you extract them) to the appropriate directories on your phone.