Apple's iPhone provides for many conveniences as a cell phone, but there is a decided lack of personalization that the owner can add to it. Changing the color of the "bubbles" that contain the text being sent or received from the short message service cannot be changed by the owner unless the iPhone has been modified. The modified iPhone allows the owner to change the color of the bubbles, and it is not illegal to do--although Apple frowns upon the practice. Changing the color of the bubbles will let you add a more personal look to your iPhone.
Wake up the iPhone by pressing the "Home" button at the bottom. Swipe the slider to the right to unlock the iPhone. Tap on the icon of the "Installer" app.
Tap on "Sources," choose "Edit" and select "Add" in the window that appears. Enter "http://apptapp.saurik.com" in the open column.
Wait for the file to download to your iPhone. Restart your iPhone.
Wake up your iPhone. Tap on the icon of the "Cydia" app.
Tap on "Sources" select "Edit" and choose "Add" in the window that appears. Enter "SMS" in the open column.
Tap to select an SMS package from the list. Restart your iPhone after the SMS package has downloaded.
Wake up your iPhone. Tap on the icon of the "iFile" app.
Tap on the "var" folder. Tap on the "Themes" folder. Tap on the "MSN SMS" folder.
Tap on the "Bundles" folder. Tap on the "com.apple.mobilesms" folder.
Click on the "Edit" button. Change the "com.apple.mobilesms" name to "com.apple.chatkit."
Click on the "Done" button. Press the "Home" button to return to the Home menu screen.
Tap on the SMS icon. Send or receive a text message with the bubble now a different color than it was before.
Download a few SMS packages since you cannot tell beforehand what color they will change the text bubble to.
Updates to the iPhone's operating system from Apple can "break" the jailbreaking and require you to modify the iPhone again from scratch.