Clarification on Roaming and G4 Network

[unimatrix001]

I am a little confused about roaming.

What is it?

When does it kick in?

When do the charges actually apply?

Also, is the Droid 2 capable of utilizing a G4 network?

[Ms_Shonta]

Provided below are two links with information on Roaming and 4G Network.

http://b2b.vzw.com/international/Roaming/

http://support.vzw.com/clc/faqs/VZAccess/4g_mobilebroadband.html