Can I use Wi-Fi app on old iPhone not in service?

I'm considering sports video cams that use Wi-Fi apps as the best way to control the device. I have an old original iPhone that isn't in service, but I have Wi-Fi in the house (where I'll be using the cam on my musical instruments).

Will it be possible to do this? I'm completely uneducated on these phones. I only have this phone because it was given to me.

I have an iphone 3g that isn't in service, but uses Wi-Fi like an ipod. As far as the other part - sorry I don't know.
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Yes you can do all that. Like the previous post it is essentially an iPod touch with Wi-Fi.