HTC's Android-powered Aria smartphone is available exclusively from AT&T, but the Aria supports multiple GSM frequency bands and can operate on wireless networks all around the world. Before you can use your Aria with a SIM card from another carrier, you must enter a special "unlock" code into the phone to disassociate the device from AT&T. Each Aria mobile phone has a unique unlock code, which must be obtained from the wireless carrier that originally activated the phone.
If you purchased your HTC Touch 3G directly from your wireless provider, chances are it's locked and can only be used with that provider's network. Most carriers participate in this practice to discourage you from leaving, but with the help of a unique unlock code you can use your phone with any SIM card. Your carrier may provide you with this code free of charge. If you have difficulty obtaining the code from your provider, use a phone unlocking service to obtain the code.
If you happen to be good at Rock Band, it might be easy for you to unlock all the songs the tried and true way, by actually playing until you beat the game. If you don't have the time or the skills, but you want to play all the songs anyway, there's an alternate way to unlock all Rock Band songs on your PS2, PS3 or Xbox 360.