A real life party? There is no such specific feature for that (yet), but you can send them a message through the PSN.
yes
With Skype
no, you can not use the PS3 as a phone however, if you want to talk to one of your friends who has a headset, go to the friends tab an click start new cat. you must have a headset aswell.
just get a Bluetooth PS3 headset
There are procedures that are described in the PS3 when you try to add friends and involve sending a message to someone
Xbox 360 if you are into battle and fighter games, if you are into fifa and those sorts of games you are should get a PS3. Also if you friends have an xbox then get an xbox so you can all talk and play with each other.
No the PS3 and Xbox 360 are on different networks
If they also have a PS3 you can add them,
If your friend has a ps3 and you both have psn accounts then yes
well you can get messages from friends and you forward it to your friends and it will give you 10.00 to 50.00 ps3 online money to spend after a week
Yup, your playstation network account is separate from your PS3.
There are headsets on sale at multiple stores that enable voice communication on the ps3.
no.