If there's ever too much of a good thing, the VOIP market is a perfect illustration. With low barriers to entry into a market just starting to emerge, there is plenty of confusion among consumers about which service provider to use. Do you sign up with Vonage because they aggressively advertise and just raised US$200-million in private equity? Or do you go with your cableco because they offer VOIP within an attractive bundle? Stepping into this selection "void" is Whichvoip.com, which offers consumers an easy way to select the best VOIP service provider based on their specific requirements. A particularly nice feature is the Web site's advanced search capability that kicks back service providers that meet a consumer's personalized needs. Whichvoip.com also offers reviews and tools to select a VOIP SP for business users. I'm not sure if there are similar sites to Whichvoip.com but the Seattle-based company deserves kudos for recognizing an opportunity and rolling out a easy to use service.
Addendum: Voxilla also has a tool to compare VOIP SPs.