In case you’ve been waiting for Sprint to finally release the Palm OS powered Centro, your wait is over. For just $99, after instant savings of $200 and $100 mail-in rebate, you’ll get the latest Palm OS based smartphone which sports the full QWERTY keyboard, 1.56×1.56 inch 320×320 TFT touchscreen, Bluetooth connectivity, 1.3 MP camera, media player, speakerphone functionality and more. If you want to get into the world of smartphone, this should be a no brainer — it’s not that easy to find a device this capable for just hundred bucks. That’s with an appropriate plan, but what the hack…