When it comes to different themes on the iPhone the sky is the limit. All you need is a jailbroken device and a willingness to install WinterBoard. Although some say the tweak saps their battery life, there are a variety of high-quality themes available, all of which can be removed if they cause a problem. LS Squares is an interesting theme that modifies the iOS lock screen with a look similar to Windows Metro tiles.
The theme works particularly well with some other tweaks to help refine the appearance. First of all, LS Squares requires some more advanced setup to select which city's weather is displayed, the language and default units for temperature. When downloaded from Cydia, LS Squares is set to display weather information from Los Angeles. Changing this requires editing a text file on your iPhone.