“How do I use tether through my BlackBerry for my Xbox 360 with no computer involved? I have the USB cord for the BlackBerry and directly plugged it into the Xbox 360. I don’t know how to get the Xbox 360 to read the BlackBerry connection.”
Attempting to tether Xbox 360 to BlackBerry phone hardware is a complicated proposition. Unlike your laptop, you can’t just connect your BlackBerry to a USB port on the Xbox 360 and expect to get connected to Xbox Live. The Xbox isn’t designed to support what is effectively a USB modem. There are ways you can use the BlackBerry data plan and connect to Xbox Live.

The primary way to use your BlackBerry data plan to connect your Xbox 360 to Xbox Live is to tether the BlackBerry to a CradlePoint personal hotspot. By using any of the CradlePoint routers, you connect your BlackBerry via USB to the router, then configure the router to share the data connection. In most cases you will still need a WiFi adapter for your Xbox 360 in order to make use of the connection.
If you want to be portable, using the CradlePoint PHS300 Personal Hotspot is a great option, because it acts as a WiFi hotspot and also operates on battery power for several hours, although that won’t solve any problem you might have in powering your Xbox 360 at the same time.