If you're using a VoIP service and have decided that it's not ready for prime-time, you may not want to cancel just yet. Unlike traditional phone services and cellular carriers, VoIP services are not required to let you keep your existing number when you switch. They might let you, but it's entirely up to them. According to the AP, VoIP carriers have lagged when it comes to implementing the onerous task of enabling number portability, with most focusing on porting numbers for incoming customers, rather than helping customers keep their numbers when they drop the service (big surprise). And while some larger services, like Vonage, allow bidirectional portability, others have taken advantage of the legal gray area to limit where customers can take their numbers; BellSouth will let you take your number to a fixed-line or cellular carrier, but not to another VoIP carrier. Meanwhile, both the FCC and congress are working to level the playing field, so full portability should arrive soon. In the meantime, read the fine print, and don't get too attached to that number.