Why won't my new Samsung Galaxy S2 Skyrocket play a sound when a text message is received?

You need to set the ring tone for actual text messages in the message setting. Open your messaging application, while on the first screen that has all of your message threads. Now push the menu touch button on the bottom-left of the phone. Your messaging settings should pop up now. Go to the bottom of the selections to the "ringtone" option and select it... Now you can set the tone you want for text messages...!! The only thing that you can set in the main menu screen is the notifications ring tone, that's likely the one you changed. As for the battery issues; I recommend that you get the SEIDIO brand extended battery for the skyrocket, it will make the phone totally usable for the entire day, sometimes longer with light use. The large screen is what uses the most power, so the more you have the screen on, the less battery life. The extended batteries take a crucial few charge-up & deplete cycles before the battery is up to it's full potential. Usually 3 full charges up and full depletions will appropriately get it set up correctly. Good luck with your new phone...!! I love my phone, so I hope you will be just as happy with it after the battery upgrade...!!