T-Mobile has just announced that it's expanding its Sidekick line of smartphones by adding two new models this fall ? the Sidekick LX and Sidekick Slide.

Sidekick LX

The new signature model in this line will be the Sidekick LX, which will boast a number of firsts for this series. For example, it will have a 3-inch, WQVGA (400 by 240 pixel) screen that uses high-definition Sharp Aquos LCD technology.

This device will also include a 1.3 MB camera with flash and enhanced media capabilities. It will be the first Sidekick that can attach images to text messages, too.

Its microSD slot will support SDHC cards up to 4 GB in size, allow users to store large amounts of multimedia files.

T-Mobile is touting the LX's "mood lights", which will light-up with definable alerts for various communication functions.

This model will use the standard Sidekick design, which includes a QWERTY keyboard and a flip-up screen.

It will be a quad-band GSM phone with support for GPRS and EDGE but not 3G.

The Sidekick LX will sell for $300 with two-year contract. It will come in dark blue and brown.

Sidekick Slide

Motorola took some of the expertise that went into the RAZR and designed its first model in this series, the Sidekick Slide, which will be smaller than its predecessors: 4.6 in. by 2.4 in. by 0.7 in. and 5.3 ounces.

The name comes from the QVGA screen, which will be the first to slide up and down over the keyboard, rather than swivel around.

Inside, the Slide will have most of the standard set of features for this line, including a web browser, email app, IM chat program, and more. It will not, however, have an audio player or a memory card slot.

This smartphone will include a 1.3 MP camera, though.

The Sidekick Slide will be priced at $300 with two-year contract. It will come in only one color scheme: black and dark purple.

Coming Next Month

T-Mobile says both these new smartphones will debut on October 17. In the mean time, additional information on this is available from Sidekick.com.

To make room for these new devices, the standard price for the Sidekick iD is dropping to $99. The Sidekick 3 will, of course, be phased out.