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The 8700 does not have "WiFi", which is what would allow you to use your home network. It is more like a phone - you must have a BlackBerry Data Plan from your carrier in order to use it for data. Without a BlackBerry Data Plan all you will have is voice and SMS text. With the BlackBerry Data Plan you also get wireless e-mail (which is what the BB is really all about), Internet browsing, IM, etc.
Browsing is fairly easy. There are also third party browsers, like Opera Mini, available for the BB.
But you must have a BlackBerry Data Plan first.