They have both a simulator and real machines you can use. The "ibmqx5" is a 16-qubit device. The problem is that noise rates are very high. For example, just to swap two adjacent qubits (using three CNOT gates), it looks like you will incur at least 10% error. It is hard (though not impossible) to run meaningful experiments on such a noisy system.
https://quantumexperience.ng.bluemix.net/qx/editor