Testing began for the new T-Mobile myTouch 3G Slide earlier this month, but the carrier has not officially announced the device yet. Early rumors placed the phone launching around May 17th, but new information suggest the release date has been pushed back a couple weeks. TmoNews is reporting the myTouch 3G Slide is now scheduled to appear around June 2nd.

T-Mobile is also set to launch the Android-powered Garminfone this spring so it will be interesting to see which phone hits first. Both devices feature similar hardware specs (600 MHz ARM11 with 3.5 inch display), but the Garminfone runs Android 1.6 while the Slide includes the new Android 2.1.

The Slide has generated the most buzz for an upcoming T-Mobile phone, while customers have been unimpressed with the Garminfone. We should be reviewing both phones in the next couple of months so we will put them head to head. For more details on the Slide, check out our early impressions and the screens from the Espresso UI.