Solid state relays are extremely simple to wire, very reliable and the inputs can be driven directly from an Arduino output. No current limiting resistor is required. Here is one example: http://www.ebay.com/itm/Solid-State-Relay-SSR-25DA-25A-250V-3-32VDC-for-Temperature-Controller-CY-/370958093286?pt=LH_DefaultDomain_0&hash=item565ed34be6