Network Computing presents a primer on the very complicated subject of EAP: 802.1X, the port-based authentication protocol, works hand in hand with EAP, a generic method of passing messages. Because EAP is not, by itself, secured, forms of EAP paired with 802.1X form the backbone of enterprise wireless and wired LAN secure authentication and operation.
Frank Bulk helps define which EAP types are appropriate for which kinds of platform environment. We're nowhere near any kind of unity on that. It's possible that the adoption of EAP-TTLS by EarthLink for its municipal-scale authentication could push that form into wider use, but it's a specialized case they've chosen it for.