An alternative to hotsync via the USB cable is hostsync via Bluetooth. But the hotsync cable is cheap. If you don't have the one that was originally packaged with the Centro, you can buy one from
www.palm.com. The Palm TX hotsync cable is interchangeable with the Centro's.
If you have a utility like FileZ, you could use it to copy an application's ".prc" file from the card to the device, but I don't know if that is sufficient to install it.