1. A parking system, which comprises: a) plurality of Curb Devices, each Curb Device having its own unique Curb Device ID and is installed close to a corresponding parking space; b) plurality of Car Devices, each Car Device is provided with its own unique Car Device ID, and is positioned at a corresponding car at a location which is visible from the outside; c) a Host which is provided with Users Data and Parking Spaces Data, for remotely managing, connecting between a specific parking car and a specific parking space, billing, enforcing and controlling on line and in real time parking of vehicles at each of said parking spaces; wherein: (A) each Curb Device further comprises: A1) a sensor for sensing coming and leaving of a vehicle within the respective parking space and providing indication accordingly to a controller of said Curb Device; A2) a Short Range RF Curb Device transceiver; A3) a Long Range RF Curb Device transceiver; and A4) a Curb Device Controller for: upon sensing the approaching of a vehicle to the parking space, sending an interrogation signal to the Car Device of said vehicle by said Short Range RF transceiver; in response to said interrogation signal, receiving the ID of the Car Device, and forwarding request for parking to the Host via said Short Range RF transceiver, which includes said ID of the Car Device and the Curb Device ID; receiving from the Host an approval for the parking signal, approval for a limited time parking signal, or denial of the parking signal, and forwarding the same to the Car Device; and upon sensing leaving of the vehicle of the parking space, sending an end of parking signal to the Host; (B) each Car Device further comprises: B1) Short Range RF Car Device transceiver for communicating with a Curb Device; B2) lighting means for giving a visual indication from the exterior of the car, for a valid parking or invalid parking; B3) a Car Device microcontroller for: receiving said interrogation signal from a Curb Device via said transceiver, and sending in response said ID of the Car Device; upon receipt of approval from a Curb Device, initiating a parking session during which a clock is activated for counting the period of the parking, while further providing said valid parking visual indication, or upon receipt of a non-approval for a parking from a Curb Device, providing said invalid parking visual indication; and at the end of a parking period, terminating said clock; (C) the Host further comprises: C1) a Users database which stores for each Car Device a User Data Record, which details at least the ID of the Car Device given to that user, the License Plate of the car to which the Car Device has been assigned, and personal details of the Car Device user to which said Car Device has been assigned; C2) a Parking Spaces database which stores for each Parking Space a Parking Space Record, which details at least the regulations applied for this specific Parking Space, and the cost per minute of parking in said parking space; and C3) a control unit for: upon receipt of said request for parking from a Curb Device, and having the Curb Device ID and Car Device ID, comparing the corresponding user data record with the corresponding Parking Space Record, and issuing one or more of: approval for the parking signal, approval for a limited time parking signal, or a denial of the parking signal, and forwarding to said Curb Device, and further, initiating a parking session for this request if said approval was issued; and upon receipt of an end of parking signal from the Curb Device, terminating the parking session, counting an accumulated charge for the parking, and billing said user.