It's a pretty simple check. On your solenoid you will have four terminals. One large terminal going to the starter, one large terminal coming from the battery with a few extra leads coming off it for accessory power, one ground terminal, and one small terminal with a wire coming from the ignition switch through the neutral safety switch (should be yellow/red I believe).
To test it simply jump the small terminal coming from the ignition switch to the terminal coming from the battery. If the starter turns the solenoid is good. If not you need a new one.
You can also check to make sure the solenoid is getting its signal from the ignition switch by using a test light on the ignition switch terminal when you turn the key to start.
Aaron:cheers: