Hi Melody!
Man there is some real techies in here
Headphones are nice when you want to use your pc like a phone, get the headphones with a built in mic and get your gamer son to get a set. Or if he has them already your set to go!
Use the instant message program (I use windows messenger, but any will do) to talk to your son, or anyone else that has headphone/mic set up. You can also use just a mic and your speakers if you already have that instead. This way he doesnt need to use the phone.
Im pretty sure your son has this as us gamers love to use a program called teamspeak that allows everyone to communicate in game.
I think it is sooo cool your learning all this stuff. One thing about DSL. It can get slow during peak hours. The more people using the same lines will sometimes make the surfing a bit slower. That is why sometimes the cable, although fast will have times where it acts like a dial up.