This is a HTML5 implementation of a APRS decoder. It uses the WebAudio API to connect to your sound device inputs and attempts to decode AFSK modulated APRS packet data. You can also run the decoder on raw test data (A packet I recorded from the ISS).
There is a Stand Alone Web App version of this that can be run offline for portability here.
For a detailed explanation on what is going on behind the scenes check out this page.
If packets are coming in too slow for you just leave this tab open and come back to it in a few hours and there should be lots of interesting stuff to see on the map.