Congratulations for carrying on the dissemination of ukulele love and knowledge throughout the world!
Here's something I prepared. Feel free to use it if you like. Make copies if you need more.
http://www.4shared.com/file/123858410/4f4615dc/Free_Songbook_Master.html
My suggestion is to help them really get a 'grasp' on learning to identify, form, and be able to change
from chord to chord smoothly at a consistent rhythm BEFORE teaching them songs.
It can get frustrating when the carrot is so near, but one hasn't the skills to reach for it. That is,
lack of chord knowledge and one's inability to change from chord to chord in time with the melody
of the song.
A strong foundation, carefully laid out in the beginning, will pay rich dividends after a few hours of
practice. Imagine your second session with students who can recognize several chords, can form them
easily, and can transition from chord to chord. With students at that basic level of skill, learning songs
will be a lot more enjoyable.
So again, help them get to that level of basic skill and it will benefit both them and you.
Happy uke-in,