Recently I was doing some work in a hospital and my cell phone would not quit rebooting. The phone is a BlackBerry 8320 Curve provided by T-Mobile. At first I could not figure it out but I figured it must be something with the environment. Finally I noticed from my laptop that there was a linksys SSID being broadcast and previously my phone had connected to a linksys SSID at a clients office. The difference here was the fact that the linksys SSID being broadcast belonged to a wireless N router instead of the previous one that was only a G router.
To resolve the issue I turned wireless off on the Blackberry by visiting the home screen, clicking on the Manage Connections icon, and removing the check by Wi-Fi. My phone did not reboot again once wireless was turned off. Just remember once you leave the location that is causing you the problem to turn wireless (Wi-Fi) back on.