Sprint today released its first dual-mode phones for the Sprint and Nextel networks, giving it for the first time since its acquisition of Nextel a voice solution that bridges its two separate networks.

The new phones, the Motorola Buzz ic502 and Blend ic402, use the CDMA 1X network for cellular voice and data access and the iDEN network for push-to-talk. The deal finally gives Sprint customers access to one of Nextel’s most prize assets, its highly functional and dependable walkie-talkie service, the carrier’s mainstay throughout its existence.

Sprint is naming the line PowerSource to distinguish it from its normal CDMA-only service. Many of the PowerSource plans will resemble those of Nextel’s, offering bundled voice minute and push-to-talk services starting at $40 a month, and unlimited push-to-talk at $5 a month.