Yes it can.
Yes, The PS3 Has wifi,indeed.
Yes the ps3 has wifi built in.
The PS3 WiFi is to connect the PS3 to the internet and not to another WiFi device
Yes the PS3 slim includes support for Wifi B and G
There is no WiFi button. That is on the router
yes but u need a ps3 and an adapter that connects to the ps3 and the psp
All models of the PS3 except the first 20 GB model have WiFi
No the USB ports on the PS3 are not able to be used for an internet connection see related link
Yes if you have internet service with WiFi also
No you must use WiFi or ethernet to connect to the PS3 and can not use a USB dongle as the USB port can not be used to provide internet for the PS3
Yes.
You can not share your phone wireless internet with your PS3. The PS3 will search for a WiFi connection and if one is found it can be used to connect to the internet. If you have internet service it is not a problem to connect to the PS3