The Voice over Internet Protocol (VoIP) market is finally emerging, and distinct market segments are taking shape, according to In-Stat/MDR. The high-tech market research firm finds that a wide variety of IP phones and other end point devices are being developed to offer access to current VoIP services and future integrated voice/data/video multi-media applications. As a result, IP phone shipments are expected to experience a 43% growth rate in 2004 alone. The migration to IP telephony in enterprise markets is happening today. In 2003, over 5.5 mln IP PBX lines were installed worldwide. Hosted services, such as IP Centrex are still in their infancy, with slightly over 20,000 seats deployed in 2003. Over the next few years, IP telephony will gain momentum in small business markets, as well. Consumer IP telephony is also growing, but will remain small compared to the PSTN because it is based on long-distance cost savings alone. Best-effort grade VoIP services, such as Packet8 and Free World Dialup, are growing substantially, but still reflect a small fraction of the total market. Mobility will be a key factor in VoIP market development. Dual-network, Wi-Fi/cellular services may be the killer application that will drive VoIP into the consumer mass market. Except for vertical industry applications (such as healthcare) that are driven by mobility requirements, the corporate market for stand-alone wireless handsets will remain small.