ok .. so can u tell me how can i make a blackberry data plan ? on steps plz ?

Call your carrier.
Ask them to add it to your account; it is not free.

i need to pay for a blackberry internet every month ? or they just make me a data plan and that's all i can install third apps on my phone ?

It is a monthly charge

You cannot download apps over the air without the BlackBerry browser, which requires the data plan. You do not need the data plan to do desktop installs. But as pointed out already, you will need the data plan to use the apps if the apps require access to BlackBerry data services.

facebook works ?

With a data plan, Facebook works great!

I can not find ''rogers" logo on bb8820? can you help

Ummm.... What?

Generally the carrier logo is under the keyboard.

--Phil