CCLI handles all of the legal and royalty issues for you. You simply keep track of all of the songs that you use in your services and report it once a year. You can also purchases service that provide chord charts, lyric sheets, vocal scores, etc.
Worship artistry is the best site to learn all the individual instrument parts for the modern worship songs. They teach you to play the songs as they are on the recording. For lead guitar parts especially, this is the best site for learning your parts.
All of the music is doctrinally rich and the resources are free!
From their website: “As a ministry of The Austin Stone in Austin, TX, we are dedicated to proclaiming the beautiful gospel of Christ in our city and to the world. Austin Stone Worship is a collection of worship leaders, musicians, songwriters, storytellers and artists serving and equipping the Church with content rich in theology, mission, and expression.”