Many tech bloggers have spent the day complaining about AT&T's new wireless data pricing structure -- and in many cases they're making good points. But if you're an existing customer of the carrier, the bottom line is that you have a decision to make. And there's a decent chance that you could end up saving some money.

However, there are also a number of catches to keep in mind.

In the process of sorting this out today, we asked and received answers to quite a few of our questions. Here's a rundown of things to know as you weigh your options, ranging from the important to the slightly random.

The big picture: Starting next week, AT&T is moving from its standard $30/month, unlimited wireless data plan to a tiered pricing structure: $15/month for up to 200 MB of data/month, or $25/month for up to 2 GB of data/month. That's where the potential cost savings come into play. But keep reading, because there's lots of stuff to consider, depending on your situation.

How much data is that? As a guideline, AT&T says 200 MB is enough to send or receive 1,000 emails without attachments, 150 emails with attachments, view 400 Web pages, post 50 photos online, and watch 20 minutes of streaming video. AT&T says 65% of its mobile smartphone customers would be eligible for this plan, given their current usage, and 98% use less than the 2 GB limit on the higher-priced plan.

Can you stick with your current plan? Yes, existing customers are grandfathered in -- they can keep their current data plans indefinitely, even when they renew their contracts or get a new phone, according to a company spokesperson. But once you switch to the new tiered pricing structure, you can't go back to the previous unlimited one. Which is why it's important to weigh this decision carefully.

What if you accidentally use more data under the new plans? Under the 200 MB, $15/month plan, you'll be charged $15 extra for an additional 200 MB if you exceed your original 200 MB allotment. Under the 2 GB, $25/month plan, you'll be charged an additional $10 for an extra 1 GB of data that month.

Can the new data plans be split across two or more lines on the same account, such as within a family? This was the devious question I came up with after seeing that the overall data usage in my family totals much less than the 2 GB allowed by the $25 monthly plan. Since we currently pay $30 each for data on two phones, or $60 total, I was hoping to reduce that by $35, to $25. Unfortunately, the answer is no -- each data plan applies to a single phone line. But if you have light data users in your family, switching them to the $15/month plan could save quite a bit.

How to check your stats: Call *DATA# from your phone to get a text message with the usage levels for your current billing cycle, or go to att.com/wireless and log in to your account to see your historical usage.

But keep in mind: The next version of the iPhone OS will introduce multitasking, allowing users to run third-party applications and data services in the background, which could end up increasing your data usage beyond the levels you're seeing currently.

What about iPhone tethering? Here is where things start to get ugly. AT&T is finally introducing the ability to use an iPhone to provide a mobile Internet connection for your computer. However, to get tethering on the iPhone, users will need to use the $25, 2 GB/month plan (dubbed "DataPro") and pay an additional $20/month without getting any additional data capacity beyond the 2 GB. In addition, you can't get iPhone tethering if you stick with your current, unlimited iPhone data plan as an existing, grandfathered customer. This whole situation is what's prompting many of the complaints today.

What about existing, non-iPhone users who tether their phones? According to AT&T, existing customers who are already tethering can keep their current tethering plan – which provides 5 GB of data for $30 per month – as long as they also keep their $30-per-month data plan. However, existing customers who do not currently have the $30 tethering plan will need to switch to the DataPro plan and add the new $20 tethering option. In addition, the company says, if a smartphone customer who’s currently tethering switches to an iPhone, that customer will need to switch to the DataPro plan and the additional $20 tethering option.

Wireless Hotspots: The new plans will include the ability for smartphone customers to connect to AT&T wifi hotspots from their wifi-enabled phones for no additional charge. Other computers and devices can't be connected directly to the wifi hotspots using the smartphone plans -- but as a workaround, someone with a tethered AT&T smartphone could use that feature to connect a laptop to the Internet via the wifi hotspot.

What about iPad users? Here's what AT&T says on that front: "For new iPad customers, the $25 per month 2 GB plan will replace the existing $29.99 unlimited plan. iPad customers will continue to pre-pay for their wireless data plan and no contract is required. Existing iPad customers who have the $29.99 per-month unlimited plan can keep that plan or switch to the new $25 per month plan with 2 GB of data. ... Customers who sign up for iPad 3G data service starting on June 7 will need to select either the 2 GB/$25 per month plan or the $14.99/250 MB per month plan."

Finally, be forewarned that after reading this, you may know more than the AT&T representative making the changes in your account, as was the case when I called the customer service line this morning.

If you have any further questions or issues to clarify, let me know at toddbishop@bizjournals.com or in the comments below, and I'll do my best to find out the answers and post updates.