Sprint PCS launched its version of push-to-talk Monday that lets customers use their wireless phones as if they were walkie-talkies.Sprint PCS\u2019 Ready Link service is the third of its kind to hit the market. Nextel Communications, with its 12 million customers, cornered the market for more than 10 years with its DirectConnect service. Verizon Wireless was the second to introduce a service with\u00a0its push-to-talk launch\u00a0in August.Like its competitors\u2019 offerings, Sprint PCS\u2019 Ready Link service lets customers talk one-on-one or in groups of up to five by pushing a button on their phone rather than having to dial a number and wait to be connected. Such services have proved popular among businesses, especially for people working outdoors who use them for short, frequent conversations.Sprint PCS is demonstrating the service at Comdex in Las Vegas this week.Ready Link plans cost $15 per month for unlimited use, in addition to a standard voice services plan that starts at $35 per month. Customers have the same phone number for both their voice and Ready Link services.Sprint also unveiled two phones from Sanyo for the service, one in a clamshell design and the other in a more durable, "ruggedized" form. Both have built-in speakerphones and can browse the Web and access e-mail. They're each priced at $300 with rebates of up to $150, depending on the service agreement.The carrier plans to introduce a third Ready Link phone by the end of the year that includes an integrated digital camera, says a company spokeswoman.Earlier this month Sprint\u2019s CEO Gary Forsee said Sprint would roll out a \u201cvery competitive\u201d push-to-talk service\u00a0by year-end.\u201cWe expect our (push-to-talk) product to be very competitive\u2026 more competitive than Verizon\u2019s,\u201d Forsee said. \u201cWe expect to have a wider array of devices available in terms of launching with multiple manufacturers in our portfolio. We\u2019re very pleased with our approach.\u201dVerizon Wireless is only offering customers one Motorola devices that supports push-to-talk.Forsee said Sprint PCS\u2019 service would be reliable and would perform as well as Nextel\u2019s services. \u201cWe\u2019re very bullish on push-to-talk.\u201dTo use Sprint PCS\u2019 service all parties must have a Ready Link phone and be on Sprint's wireless network. The feature is not available to customers when roaming on another carrier\u2019s network, but the carrier\u2019s standard voice services are.Network World Senior Editor Denise Pappalardo contributed to this story.