If you're just looking for information on how to construct borders, I'd go with a book or video. I have the Janet Kime book mentioned by ManiacQuilter2 and it's good, but
very basic. The complete title is
The Border Workbook: Easy Speed-Pieced & Foundation-Pieced Borders.
A more complete reference book that covers both design and construction considerations might be
Pieced Borders: The Complete Resource by Judy Martin and Marsha McCloskey but you may have to get it from a library as it's a 1994 book.
http://www.amazon.com/Pieced-Borders.../dp/0929589033
If you're primarily looking for advice on how to choose borders that best compliment the body of a quilt, I'd look for a class. You're apt to get more of the design aspect than you'd get elsewhere. Quilt University had a great free class on borders, but that's no longer an option and I know nothing about the Craftsy class.