> Does anyone know where I can find a land line phone amplifier?
You can still buy the pickups that are intended to record phone conversations
and just use any normal amp to amplify with them, from Radio Shack etc.
> Also, is there an amplifier feature on any cell phone?
Yep, there are heaps of those, mostly intended to be used in cars etc.
By googling "telephone amplifier".
Also, is
> there an amplifier feature on any cell phone?
Depending on what you mean. My Nokia 1208 (which is probably about as
cheap as a cell phone can be) has adjustable volume, and if that's not
enough it has a speakerphone setting.
Dave