The wireless industry gets a bit jumpy when it comes to net neutrality regulations, but a new report from Fitch Ratings says the real danger is VoIP.

According to Fitch's biannual report on the North American wireless industry, the industry would have naturally evolved toward net neutrality because of long-term competitive pressures: The involvement of the FCC simply speeds up the process.

However, Fitch says Web-based voice (VoIP) and text messaging will have "uncertain and wide-ranging" implications for operators. IP-based services cost less and could significantly erode average revenue per user, particularly if national operators shift en masse toward unlimited calling plans.

Together with the regulation of net neutrality rules, carriers will have to make major changes to service plans to maintain their bottom line. For instance, carriers may charge higher rates and put data caps in place to mitigate the impact of high-bandwidth content on network quality.

Carriers are already worried about this, particularly AT&T. The carrier allows iPhone subscribers to use VoIP to work over a Wi-Fi connection but not over AT&T's 3G network.

In an August filing with the FCC, AT&T said it would take another look at authorizing VoIP capabilities on the iPhone for use on AT&T's 3G network but has given no formal indications that capability is coming any time soon.