t's not really a card, but more of a pearl jewelry service. Among other things, it allows you to change the phone number that shows up on someone else's caller ID to be whatever you want it to be. In that way, you can represent yourself to a friend as someone you are not – and pull off a clever practical joke. You can place calls directly from the SpoofCard website, or you can download an application for your cell phone.

In a SpoofCard use that may be more sinister, however, people can change the caller ID number to match the number they're calling. On some phones, that is enough to be granted access to that number's voicemail.

This is what Wise is alleged to have done. Prosecutors say she checked and even deleted voicemails from the accounts of four women, rivals for the affections of Wise's former boyfriends. She is charged with four counts each of computer trespassing, eavesdropping, computer tampering, and aggravated harassment, plus one count of stalking, according to the New York Post.

How do most people use SpoofCard?

According to testimonials on the biwa pearl SpoofCard website, not-so-nice practical jokes are popular. Most stories aren't G-rated, so we won't reprint them here, but here's one of the less-harmful spoofs:

"Telling my friend who is a licensed plumber that his license has been revoked due to unethical practices. It drove him nuts.... it was [sic] hillarious."

The service also includes a voice-distorter that can disguise the caller's identity or even change the tone of one's voice enough to sound like a different gender. (Imagine the fun guys are having calling their buddies as women.) SpoofCard can also be used to record phone calls.

Is it legal?

Prosecutors in the Wise case seemed to think not, at least not the way she used it.

The company says this on its website:

"Each of the capabilities of SpoofCard is legal in the US. However, certain uses may be illegal depending on which state you are calling from or to. For example, a handful of states have passed laws that make it illegal to spoof caller ID for certain purposes, such as 'to mislead, defraud or deceive the recipient of a telephone call.' Before using the spoofing capability of SpoofCard, you should determine whether the use you will make of the service is legal in the state where you are calling from and the state where the party you are calling is located.

"In addition, it is illegal under the law of numerous states to record a telephone call without informing the other party that the call is being recorded. Before using the recording capability of SpoofCard, you should determine whether it is legal in the state where you are calling from and the state where the party you are calling is located to record the call without informing the called party. If you do not know whether such recording is legal in both states, you should protect yourself from possible state criminal prosecution by informing the other party that you are recording the conversation. SpoofCard cannot monitor conversations to determine whether they are being legally spoofed or recorded. SpoofCard disclaims any and all liability or responsibility for your use of the akoya pearl Card's spoofing or recording capability."

These cautionary notes apparently aren't deterring people from using SpoofCard. The company reports that its iPhone application has been downloaded more than 30,000 times. (It has similar products for Blackberry and Android mobile phones.) While the applications are free to download, calls cost $4.95 for 25 minutes in the US