Word is that time will soon be up for those of you who are using the popular MyWi app to turn your iPhone into a hotspot for other devices.

If you are one of the those type of users, you may have seen a letter to you suggesting that you opt-in to one of their data tethering plans. Failure to do so just may prompt AT&T to do it for you. Below is the partial letter with instructions on how to bring your plan up to snuff:

Dear [Name of Account Holder],

We’ve noticed your service plan may need updating.

Many AT&T customers use their smartphones as a broadband connection for other devices, like laptops, netbooks or other smartphones– a practice commonly known as tethering. Tethering can be an efficient way for our customers to enjoy the benefits of AT&T’s mobile broadband network and use more than one device to stay in touch with important people and information. To take advantage of this feature, we require that in addition to a data plan, you also have a tethering plan.
Our records show that you use this capability, but are not subscribed to our tethering plan…

…If we don’t hear from you, we’ll plan to automatically enroll you into DataPro 4GB after March 27, 2011. The new plan – whether you sign up on your own or we automatically enroll you – will replace your current smartphone data plan, including if you are on an unlimited data plan.

If you discontinue tethering, no changes to your current plan will be required.

The letter also outlines AT&T’s current pricing structure for tethering plans and offers key advantages to using the plans.

In the end, Federal regulators have said that jailbreaking is not illegal, it can however, according to Apple, void your warranty. And be advised, you are at risk if you decide to jailbreak your phone, and the companies reserve the right to treat you differently if you choose to do so. So opting into one of AT&T’s data plans for small business can keep you on its “nice list”.