T-Mobile USA unveiled today a new phone, Samsung Katalyst, that supports the carrier’s T-Mobile HotSpot @Home service. The service, launched in June this year seamlessly switches subscribers back and forth between cell phone calls and calls made over Wi-Fi, for an additional charge of $19.99 a month.

The customers of HotSpot @Home service can also make calls using T-Mobile Wi-Fi hotspots at about 8,500 locations nationwide that include popular venues like Starbucks.

Samsung Katalyst offers built-in support for T-Mobile HotSpot @Home and it has a has a sophisticated metallic silver finish on its slider design.

Known also as Samsung SGH-t739, Katalyst has a 176 x 220 pixels TFT display and it weighs 4.1 ounces (with standard battery). Its dimensions are 3.97″ x 1.98″ x .65″ and it is a GSM/GPRS/EDGE-enabled phone.

Katalyst includes also Bluetooth wireless technology and its memory is expandable through a microSD memory card.

Samsung Katalyst has also multimedia capabilities, thanks to a integrated music players and 1.3 mega pixel camera.

The Katalyst also features advanced messaging capabilities such as instant messaging that enables instant chat and support for AOL, ICQ, Yahoo! and Windows Live Messenger.

Samsung Katalyst costs $79,99 with a mail-in rebate and a two-year subscription to T-Mobile.