Can a Blackberry Pearl 8100 with an unlocked GSM sim card work on a Rogers plan?

There are two types of cell phone networks, GSM and CDMA. As long as the network you are trying to move your unlocked phone to is compatible then yes it will work. In most cases a GSM phone will not work on a CDMA network and vise versa, however, some careers (such as Verizon) have support signals for GSM phones. There is no support for CDMA phones on a GSM network at this time. So for overall versatility, GSM phones are better.