From the home tab tap the clock to bring up the world clock. It may be set to My Location. Click the Add City at the top and add your city. Once added, select it to make it the local city. Return to your home tab and both the clock and weather will be aligned to your new city.
EDIT: Actually, you didn't state what ROM your using, but my instructions were for Manilla 2.5. I'm not sure if the original Manilla 2.1 works the same or not, but give it a shot
