Surfing the web from a mobile device can be a great business tool, or a costly mistake. It could even land you in jail.

It all depends on whether or not you really understand what you're doing.

Alykhan Jetha, president and CEO of business software developer Marketcircle, Inc. in Markham, Ont., is quick to offer a cellphone data horror story.

"One of my friends, actually a customer of ours, by mistake turned on the EDGE (fast data-speed setting) and was checking mail and his bill came to $1,700," Jetha reports. "He called and complained, so they (Rogers Communications Inc.) gave him a $200 deduction."

It's not the sorriest tale of cellphone data use gone horribly wrong. Albertan Piotr Staniaszek, 22, signed up for Bell Mobility's promotional "unlimited data plan" for the iPhone-like HTC touchphone.

He figured that unlimited meant unlimited. So he downloaded data, music and high-definition movies through his cellphone to a laptop computer. Imagine his surprise when he got a whopping $85,000 bill from Bell Mobility.

Staniaszek protested that he was never told he would be charged on a per-kilobyte basis for what he did. Bell adjusted the charge to $3,243 - a hefty phone bill, even for a Fort McMurray oilfield worker.

Young Piotr's crime was something called "tethering" - using his mobile phone as a modem for a computer.

To be fair to Bell, that practice was explicitly excluded from the "unlimited data plan.”

To be fair to Piotr, "unlimited" has a common dictionary definition that doesn't include a surprise $85,000 phone bill.

Doesn't anybody at Bell keep track of usage and cut you off when it gets obviously unreasonable? Or is it all about greed?

Jetha figures it's definitely greed. Canadian users generally pay higher cellphone data rates than, say, Americans, because, Jetha says, the carriers are "just too cozy with the current arrangement.”

He blames the CRTC for not pushing harder for better deals for Canadian consumers.

He also claims the real reason we haven't seen the Apple iPhone in Canada is because Apple requires carriers to have an unlimited data plan to sell the iPhone. Jetha should know, since his mainline business is creating billing and related software for Apple platforms.

There's certainly no technical hang-up, at least for Rogers Communications Inc. and its wholly owned subsidiary, Fido Solutions. After all, Jetha spoke with me on a Canadian cellphone network with an unlocked iPhone that he bought in Buffalo.

For now at least, Rogers has the lock on the iPhone market in Canada, since it has the right (GSM) network for the current iPhones. Bell and Telus use the CDMA standard.

Every time I call Rogers to ask for a Canadian iPhone release date, the company has no comment.

Of course, just buying the popular BlackBerry with a data plan and grimacing while paying the bill every month is how most people deal with their mobile data needs. Almost every Canadian government official of any stature is constantly pecking at his or her BlackBerry. Teenagers are now getting them, so their value as a status symbol may be waning.

As long as you're just checking e-mail and the boss is paying the bill, the BlackBerry is a pretty neat business solution. But if your business or pleasure involves big downloads, media-rich surfing, or, heaven forefend, watching TV as a data stream, that $6-$12 per megabit really does add up.

BlackBerry maker RIM is well aware of this. Some of its new models allow you to switch from cellular to WiFi to surf the web. Just find yourself a hotspot.

Hotspots are popping up in bookstores, coffee houses, and even mom 'n' pop retail shops.

Many are free, or allow you to pay by the hour and can provide full web surfing, e-mail and even free VoIP calls. Whole airports and even city cores are becoming hotspots.

Being too lazy to get an unlocked iPhone, I'm still having fun with my Sony Mylo (found online for US$210). This spiffy little device looks like a PlayStation Portable, so I just hang with the gamers sitting on the floor at the airport.

But while they're destroying alien invaders, I'm making free phone calls, using Google Chat and checking e-mail, all with no contract and no monthly bill.

The screen is a little cramped but, hey, it works. One downside is the miniature pull-out keyboard. It would be especially suitable for a small child or a midget monkey.

Do be careful where you connect. The long arm of the law is starting to come down on those who piggyback without permission on open hotspots.

A bill proposed by Maryland state delegate LeRoy Myers, Jr. would make intentionally freeloading on WiFi a crime punishable by a fine of up to $1,000 and up to three years in jail. He argues that an innocent person might be charged with hacking, when really it was that seedy character in the parking lot that did the mischief.

Myers, it should be noted, is the same legislator who sponsored a wacky bill to ban the display of fake "human or animal genitals, human buttocks, or human female breasts" on motor vehicles.

He was apparently disgusted by fake bull testes hanging from a pickup truck. His Internet bill just got an unfavourable report by the judiciary, so it seems it isn't going anywhere either.

Singapore and the U.K. are way ahead of Myers, anyway.