Online PLC Structured Text Programming Simulator
Online PLC Structured Text Programming Basics Training Course using free Codesys PLC Simulator to get hands on experience.
Siemens PLC Simulator - Plant Simulation Software
This Siemens PLC Simulator and Plant Simulation Software bundle make for a great Siemens training tool. Especially since both Siemens PLC simulator (s7 sps software)and the factory simulator (Factory I-O) interface with each other to give a full system hands-on experience.