Quietly, last night, AT&T revised its wireless plans. In the latest changes to the company’s service terms, it looks like AT&T is trying to exempt its own video services while prohibiting competing services like the Slingbox.

Sound familiar? I wrote about it on April 3rd. iPhone and PDA users literally felt their significant investment get less valuable. They complained, and AT&T removed the offending language by the next day, calling the language a mistake.

Guess what? It’s back!

Sometime in the past 24 hours, AT&T changed the TOS again:

This means, by way of example only, that checking email, surfing the Internet, downloading legally acquired songs, and/or visiting corporate intranets is permitted, but downloading movies using P2P file sharing services, redirecting television signals for viewing on Personal Computers, web broadcasting, and/or for the operation of servers, telemetry devices and/or Supervisory Control and Data Acquisition devices is prohibited.

This is a company that already limits users’ consumption of bandwidth (it has a 5 GB cap). As I said in my previous post, it’s not very “Internet” when the ISP is picking and choosing what legal activities you may and may not do with your connection. With AT&T prohibiting you from watching your TV, they figure that you’re much more likely to subscribe to their “AT&T Mobile TV” service.