Difference between SOAP webservice and RESTFUL webservice"

At a very basic level , SOAP is a messaging protocol , REST is a design philosophy , not a protocol. When you base a WebService on a SOAP protocol , you basically comply with SOAP rules of creating a Service Request , posting the request to server , receiving the request at server , processing the request and returning the results as a SOAP message.SOAP does not talk about the exact manner in which client benefits from the service, nor about how to design the client itself ( apart from the message it is posting ), it only tells how a message from client can be sent to service and back.
REST is short for REpresentational State Transfer. It does not specify the rules to create a message and post it to server. You can do this by simple HTTP protocol. What REST specifies is the manner in which client and server manage their states so that they become useful to the client -server communication. Here , you are more focussed on designing the states of clients and servers rather than the messages they are exchanging.