Moving SIM card between cell phones

Are there any problems/issues related to moving a SIM card from one cell phone to another? Some companies (i.e. Cingular) like to charge you an upgrade fee of around $18 when you buy a new phone (w/o changing plans, etc). The phone is someone's who no longer needs it and it is far better than my current phone....

 

Providing the phone is not locked in to another provider e.g. Verizon, you shouldn't have a problem. If the phone is locked, for a small fee of around $15, you can get the unlock codes online.

If you already have access to the phone, try it, before you buy it from them and see. I brought my phone over from the UK when I moved, unlocked it and it works fine with Cingular, rather than using the cheap crap they gave me free with the plan. HTH

 

cool... they are between the same providers