As you start advancing in your worship experience, it is important for the leadership to begin to think about sound correctly. During a live performance, the guy behind the console is the equivalent of the producer on a recorded album. You notice that the Producer is always mentioned with some respect. The reason for this is that the way the music sounds is NOT just the result of having good musicians. The decisions (minute by minute) that a producer or sound engineer makes are what makes the music sound good. From a Leadership perspective, this means that you must put great care in your selection and respect that persons viewpoint as you do your Worship Leader.
The Worship Leader cannot make decisions about the current mix while on the stage. FOH (Front Of House, an industry term meaning what the audience hears) sound is different from the stage sound. The Worship Leader cannot hear what the sound person hears. Does the Worship Leader want sound mixed for his/her own pleasure or for the greater audience? The Worship Leader must explicitly trust the sound person.
The Sound Person must be focused on reproducing the style of music desired by the church. I recommend that the church leadership specifically select a style and communicate that to the sound person (or sound team - as you grow).
As to some of the other resources - I agree with the poster that said to be careful. Too True. Many organizations are fully dedicated to promoting what they sell. I would steer clear of books with titles like "Sound made Simple". While the some tasks can be simplified, you get results proportional to your beliefs about sound. You think it is easy, you get lousy sound. You have respect for sound's complexities, eventually you will get good sound. Look for the guy/gal that has a passion for sound like your guitarist has a passion for guitar. Then give them elbow room and resources (time on the system, money for some seminars and equip).
I could go on for quite some time, I do seminars on this stuff - all donation based. I make my living doing other stuff, so I have no need to sell products or myself (Amateurs can be your greatest resource). I do it because Jesus deserves the best.
If you're interested in a seminar, I run them when demand is there from where I live in the mountains in CO. Call me at 719-748-4795. Or check into such things with local sound companies. Be aware that recording seminars are NOT the same thing. You want a Live Sound seminar.
Blessings