"STRONG BUY ALERT!!"

"The end of oil?" "New patent unveiled!"

You expect to get irritating messages like this in your email's in-box but now they're headed to your cellphone as well. Just last week, subscribers of Verizon Wireless and Sprint Nextel were bombarded with 550,000 of these breathless text messages. While it remains unclear who or what company was the sender, Verizon has already begun proceedings for a civil case once the spammer is identified.

This incident is the latest in a growing trend of cellphone spam, says Linda Sherry, a spokeswoman for Consumer Action, a consumer advocate group. The reason? More people are giving up their landlines in favor of cellphones, which means those numbers are appearing on more order and contact forms and are available for spying eyes to pick up and use use for unwanted texts and calls. (About 8.4% of households nationwide are wireless-only, according to CTIA-The Wireless Association, a trade group.)

Cellphone spam isn't just grating it's also expensive. If you don't subscribe to your carrier's text message plan, you can easily pay 10 cents for each incoming text, solicited or not. And those incoming telemarketing calls can waste precious minutes.

So what can you do to keep your cellphone spam free? Here are seven strategies:

Add your name to the list
The FTC's National Do Not Call Registryfor details, click here, there's no national telemarketing directory for cellphone numbers and no plans to create one. "It's illegal for a telemarketer to contact consumers' cellphones using an automated dialing machine," notes Joe Farren, a spokesman for CTIA-The Wireless Association. Still, the occasional call does get through, so it's worth taking 30 seconds to sign up, which protects your number for five years.

Safeguard your number
Even though your cell number is unlisted, it's still in company databases and other places (like your MySpace page or Craigslist ad) for unscrupulous types to harvest. But just because you're required to give a number doesn't mean it has to your cellphone number. Protect yourself by using one of the free services that offer disposable numbers (see our story. These services let you create an alternative number that automatically forwards calls to voicemail.

Download with care
Two bucks seems like a small price to pay to have your phone shout out the Super Mario Brothers theme. But when you download content to your phone, you may be unwittingly offering up your number to companies that will later spam you, warns Farren. So make sure you're downloading only from legitimate companies. Read the fine print to ensure that your number won't be passed along to third parties.

Opt out

Not sure why you're getting sales calls from Omaha Steaks? Could be that order you made a few months back. Whether you're signing up for a rewards program or ordering shoes online, you're usually asked to sign off that you've read and understood the company's privacy policy, says Edgar Dworsky, editor of

, a consumer advocacy site.

For tips on making your complaint heard, see our column The Art of Complaining

Read your cellphone manual
Your cellphone itself may hold the key to blocking unwanted calls and texts. But be warned: Usually, it's an all-or-nothing proposition. All calls from unrecognized numbers will be blocked, whether it's a telemarketer or oops your little brother calling from a payphone for a ride home. The exception: If you have a high-end smartphone like a Treo or BlackBerry, you can download programs like Call SMS Blocker to block specific sources.

Contact your service provider
"Cellphone companies are very interested in this problem," says Leslie Flint, a legal research assistant for the Privacy Rights Clearinghouse, a consumer advocate. But they aren't psychic. Until you complain, your service provider has no way of knowing you're receiving spam texts or annoying calls. If you ask, your provider will usually refund the charges for spam texts, or even block a certain number. T-Mobile, for example, lets subscribers determine settings online, filtering out unrecognized addresses or blocking incoming texts altogether.

Notifying your provider may also aid the larger problem of cellphone spam. Earlier this year, Verizon Wireless won a $10,000 judgment against Passport Holidays LLC, a Florida-based travel company that sent more than 100,000 spam texts.

Take your complaint up the chain
Talking to your cellphone-service provider is a good start, but there are other agencies to notify as well. Your best bet is the Federal Communications Commission, which enforces the CAN-SPAM Act. If you're receiving stock-related spam, file a complaint with the Securities and Exchange Commission and the National Association of Securities Dealers, both of which have departments to investigate spam texts.