SIM card & changing cell phone carriers?

I have a samsung double flip phone from bell and would like to go to virgin but it isn't a virgin phone. I hear about SIM cards and stuff but I have NO IDEA what this is or how it works but it has something to do with taking one phone to another company. Can you please explain what a SIM card is, how do I find it and can I change companies with my cell phone?SIM card %26amp; changing cell phone carriers?
Basiclly a Sim card is a card that allows you to have service (ie make calls and get on the internet). It's somewhat the brain of the phone, you can save contacts to it and in most phones it fits into the back under the battery. That is really the easiest way to explain it since you are not familiar with it. But Anywho, As far as using that phone on Virgin that is not possible. The main reason is because Virgin does not use sim cards. (with our going in to depth to confuse anyone). If they did then it would be a few more steps that would be needed to use that phone on a different network. I hope this answers all your questions.SIM card %26amp; changing cell phone carriers?
SIM cards r GSM technology... and bell, telus, virgin, koodo, etc. use CDMA technology and dont have SIM cards. SIM cards are little cards u put in ur fone and u can easily transpher them to a diff fone... ive done it many times. only rogers uses SIM cards, not bell and telus. they use diff stuff... and virgin is a locked network meaning u can only use phones that they cell. u Cant use a bell phone. i called and asked them... and they don tuse SIM cards. same with koodo, u can only use fones they sell not telus fones......... hope that helps! so ya a SIM card is just a little card u put in ur fone with all ur network info.SIM card %26amp; changing cell phone carriers?
A sim card is usually the card under the battery and on the sim card is like all the information like the phone number and you can only switch the sim card from phone to phone but it will still be a virgan moblie but you can't alway switch the sim card in to a random phone and expact it to work because some phones are locked to only work for that network that sells it oh and verizon don't have sim cards