Change your caller ID using BluffMyCall.com

If you've been playing jokes on friends or co-workers using 123SPOOF.com, you'll need to know that they've changed their name to BluffMyCall.com. The popular free service allows you to change your caller ID number when making outgoing phone calls. If you live in the US or Canada, you'll need to provide the information on their web site where they will give you a phone number to call to use the service. You get roughly two minutes use out of it, but at least the person you're calling won't know who it is. Paid subscribers get some nifty features like disguising your voice, recording phone calls, and international calling. So if you want to play a joke on a co-worker, you can use it to pretend that your boss is calling while making the call right from your handset. Existing customers don't need to worry about changing their account/PIN, while dedicated applications can be downloaded for devices like an iPhone, BlackBerry, or G1. There's an extra step needed if you have an iPhone; it'll only work on ones that are jailbroken. So check out their web site for more details. You never know when something like this can come in handy.

source: BluffMyCall via Cell Phone Digest