Yeah you need

1) audio in and out of your rig, to and from your computer

2) psk software to run on the computer

3) a means to PTT/TX your rig

The PTT part can be done via serial port of the PC, you can use the audio and VOX built into the rig already (I don't recommend that), or you can use pre-made interfaces that do it a few other ways.

My favorite of my three, a homebrew, a Digimaster Duo, and a Tigertronics Signalink USB, is the Tigertronics.