Many Canadians dislike spam clogging up their email -- and a growing number are now suffering from cellphone spam: Unwanted text messages that could cost you upwards of 20 cents a message.

This year alone, North Americans will receive an estimated 1.5 billion unwanted cellphone spam messages -- twice as many as in 2006.

Mike Gikas of Consumer Reports says many people are becoming victims of spam through cellular downloads.

"People don't realize they could unknowingly be inviting spam when they download ring tones, games and other stuff from vendors they don't know or trust," he said.

In the United States, cellphone users are protected from unwanted texts by the Can-Spam Act, which prohibits sending commercial messages to cellphones without "express prior authorization."

But unfortunately, this law has a lot of loopholes, Gikas said.

"For example, when you sign up for service, even from your own vendor, you're also giving them permission to send you messages as well as their partners," he explained.

This problem happens in Canada too.

While phone companies routinely block mass generated messages, random spam aimed specifically at your cellphone number, sometimes get through. This happens when people sign up for a service online or give out their cellphone number.

And you end up paying for every unwanted text.

So what can you do to minimize cellphone spam and the potential cost?

Consumer Reports suggests calling your carrier right away. You are more likely to have charges for messages waived before they pile up.

You can also block spam at the source.

"You can go to your cell account online, access preferences for text messaging and e-mail, and block text messages from Internet-based accounts," Gikas advised.

"Of course, you can still get the text messages you want from family and friends when they use their cellphones."

Gikas says this will eliminate most of the problems from cellphone message spam.

Cellphone spam destroyed Virginia Doetsch's fun of text messaging her kids. Eventually, she got so frustrated she cut off her text messaging service.

"The spam text messaging became so invasive. I really can't repeat the words, just things that were inappropriate for me to see, for my children to see, for anybody to see really," she remembered.

Text messaging can be fun, convenient and reliable. But before you are overrun with spam, be sure to check your text messaging settings.

With a report from CTV British Columbia's Chris Olsen