Pontiac Repair: 1989 Pontiac Firebird, pontiac firebird, starter solenoid

Question
Hi, I have an 89' firebird, with the 2.8 v6.  After driving the car for a little while (over an hour)sometimes it will not restart.  I am good with mechanical problems, but I am not very handy when it comes to electronics.  I was wondering if maybe it was a relay that was not engaging.  When I go to start the ignition, the dash lights come on, and the car has power, however the starter will not engage, it seems there is a relay not allowing the starter to get power, after letting the car sit for 45 minutes or so it will start right up and run perfect like nothing ever happened, do you know what I need to check to find my problem? I have a voltmeter, if you could lead me in some direction that would be outstanding.  Thanks in advance.  
Jere

Answer
i would go for a good drive then when you get home kill the engine and have a friend turn the key and try to start it while you check for juice at the starter.if the power is getting to the starter but its not cranking than you have a bad starter solenoid or the starter itself maybe bad. if you get no juice then it is probably the relay located on the main fuse block on most vehicles.