You will need to find your local AB dealer and buy the software from them... you need RSLogix and RSLinx, you can use the free version of RSLinx but for the SLC you will need the full version (not free) of RSLogix, below are the different version that are available
Catalog Number Description
9324-RL0700NXENE RSLogix 500 Professional Edition Offline/Online Programming
9324-RL0100ENE RSLogix 500 Starter Offline/Online Programming
9324-RLC700NXENE RSLogix 500 Professional Bundle
9324-RL0300ENE RSLogix 500 Standard Edition Offline/Online Programming
Starter or standard should work for you, just let your dealer know what processor you are communicating to.