We told you how to opt out of receiving junk mail, but telemarketing calls and even m-spam, or text message spam, can be distracting, disruptive and, in the case of text message spam, can even cost you money. David Pogue of the New York Times recently found out how to block cell phone spam, and decided to share his discovery with readers.

If you use AT&T or Verizon you can block all text messages sent from the Internet, which is where nearly all text message spam comes from. If you have AT&T, log in at mymessages.wireless.att.com. Under Preferences, you have the option to block certain texts. If you have Verizon, log in at vtext.com. Go to Text Messaging and then Preferences in order to block texts. Sprint does not offer auto-blocking, but you can block specific phone numbers at sprint.com, under My Online Tools > Communication Tools > Text Messaging > Text Messaging Options > Settings & Preferences. T-Mobile doesn't offer the option to block messages sent from the Internet, but you can block messages sent by email or block text messages containing certain phrases, at t-mobile.com, under Communication Tools.

In order to prevent telemarketers from calling your home, be sure to sign up for the National Do Not Call Registry. It takes less than 30 seconds to punch in your phone number and email address, and then confirm your email registration. And as of February 2008, telephone numbers places on the National Do Not Call Registry will remain on it permanently.

Various VoIP providers can also help prevent annoying, unwanted calls. Voip.com has a telemarketer blocking function, and Vonage, Lingo, ViaTalk, AT&T CallVantage, VoipYourLife and Packet 8 all have "Do Not Disturb" and "Anonymous Call Block" features that will, respectively, send all incoming calls straight to voicemail during specified hours and block any calls from callers who have deliberately blocked their caller ID. Visit our free online comparisons and reviews to learn more about VoIP services.

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