For once, I couldn't agree more with Mr. Cosby- Read on people

Using the example of computer 1 and computer 2. The TCP connection is the second segment of three used to establish a TCP connection. In step 1 computer 1 sends a message to computer 2 with its SYN bit set saying in effect that it want to communicate and synchronize sequence numbers. It sends a random number that will be used to synchronize the communications. Example would be 840973201. After computer 2 receives this message it responds with a segment whose ACK and SYN are BOTH set. In computer 2’s response the ACK field contains a # that equals the sequence # originally sent plus 1, example would be 840973202. This way it tells computer 1 it received the communication and expects it to respond with the sequence # 840973202. In its SYN field computer 2 sends it own random number which computer 1 will use to acknowledge that it received computer 2’s transmission. Then computer 1 sends out a segment whose sequence # is the 840973202 number because this is what computer 2 expects to get. Also in that same segment computer 1 also communicates a sequence # via its ACK field. This number equals the sequence number that computer 2 sent plus 1. So if computer 2 sent the # 265470938 then computer 1 would send the # 265470939. The two computer will talk this way until computer 1 sends out a Fin flag saying it doesn’t want to talk anymore