Can I activate a T-Mobile Sidekick Slide on Verizon wireless?
You cannot activate a T-Mobile Sidekick Slide, or any other T-Mobile phone for that matter, on the Verizon network. T-Mobile uses a mobile standard called GSM, while Verizon uses a separate standard called CDMA. T-Mobile phones have a SIM card, while Verizon phones have account information built onto the phone’s memory. You can, however, use a Sidekick Slide with the AT&T network.Source:CNET.com on GSM phones (T-Mobile) vs.