These are my favorites--none are new, but very complete--should be easy to find on Amazon, Alibris, etc.
Know Your Serger (In my opinion, this is the best one) ornamental techniques and make gifts as you learn.
ISBN 0-8019-8242-3
Sewing With Sergers ISBN 0935278 A must for learning how to use a serger.
Creative Serging 2nd book of above ISBN 0-935278-12-5
Serging Inspirations-Nancy Zieman. excellent leaflet
The Serger Idea Book ISBN 0-935278-18-4
fab ideas for sewing garments--I about wore this one out!
I have used a serger for 25 years--they were very pricey then, but it paid for itself many times over. I had a 4-H Horsemanship Club, and taught all the girls to sew on a sewing machine and the serger--we spent a whole summer and fall making their horse furnishings, show outfit, and school clothes.