[Sheriff Gonna Getcha]

So, I've been playing Madden for years and years, but I never bothered to buy a network adapter to play online. Now that most of my Madden-playing friends have moved out of state, I'm eager to get a network adapter. I searched for wireless adapters, but didn't find any. Could someone please let me know where I can find one? Also, what internet features are there that I've been missing out on? Is it worth shelling out the extra $$$?