Be careful about that, even at home. There are many contraindications to massage that a lot of people are not aware of. Licensed Massage Therapists take courses in anatomy and physiology and pathology,in addition to learning the hands-on portion of massage so that they can practice massage safely. It may sound funny, but if you perform massage and are not properly trained, you may do more harm than good. It may sound funny because most people think massage isn't a big deal and don't understand how it could possibly harm anyone; however, the more you read about it or the more you get trained, the more you come to realize that there are some situations in which an untrained person's massage could have an ill effect.
Being a licensed therapist, I do not agree with untrained individuals performing massage [How could I? Not only for the reasons I said, but also because that's money out of my pocket!
]. That being said, I have not seen any online manuals at all. There are a lot of books out there, but you usually need a general level of understanding of basic techniques, such as Swedish, and terminology of massage, anatomy, myology, and pathology. Pay particular attention to any contraindications when you read about any massage techniques.
One final thing, be sure that you check regulations in your area; for example, in New York State it is illegal for anyone to perform massage, even in your own home, if you are not licensed in the state. I know you can check the Office of Professions website in NYS for these regulations, but I don't know what it would be in your state. Some states do not regulate massage yet, but I would still like to warn you, just in case.