Industry insiders suggest that Verizon wireless, the second largest carrier in the US, has begun testing the iPad with a view to support the device on its CDMA and later its 4G service.

This news comes in the backdrop of news that AT&T has binned its unlimited data plan for the iPad, in favor of a capped model.

AT&T also announced today that it has cancelled its $29.99 unlimited data plan for the iPad, instead it will offer a $25 for 2GB data per month plan.

This news is just the tip of the iceberg, among other announcements that major changes might be looming in the days ahead for Apple Inc’s US carriers.

• AT&T raised its early termination fee last week for its smartphone users, again suggesting competition might be in the offing.
• AT&T earlier this week, announced support for tethering via the iPhone OS 4, for $20 per month fee.
• AT&T’s new iPhone deal saw the carrier further restructure its data plans, it is cancelling the $30/month unlimited data plan for new customers; instead it will offer new customers the Data Plus, $15/month @ 200mb of data, or Data Pro, a $25/month @ 2 GB of data to its new subscribers on the iPhone.

Discussing AT&T at D: all things digital conference yesterday, Steve Jobs said :

“AT&T took a big leap on us and decided they were going to trust us to do the right thing with the phone. And that’s worked out quite well for both of us.”