tl;dr - this sounds nuts, but it worked for me
I did this... got one of his books (they're on kindle, ibooks and audible) and read it. i had rsi that increasingly got worse over a 3 year period until i couldn't drive, tried pretty much every non-surgical thing i could find (multiple doctors, creams, physio, ART, acupuncture, TENS, stretches, exercises, posture examined by ergonomist, different keyboards, switching mouse hands, trackpads, footpedals, foot mouse (wouldn't you know it, my knee started getting rsi), vitamins, supplements, break software with increasingly frequent breaks, switched to dvorak, wacom tablet for handwriting/mouse replacement), and things were still trending worse. it was hard to hold my new daughter for more than a couple minutes, and i was trying to figure out what work i could do that wouldn't involve a computer.
i can still remember running across sarno's book online on a random google search for rsi treatments, the way people remember where they were when they heard about the challenger explosion or 9/11. within a week of reading sarno's newest book (name escapes me now, but it is offputtingly new-age sounding), i had next to no pain, after a month, i'd say i was healed. it's now been 10 months, and i don't even think about my arms anymore, or follow any sort of treatment regimen. i'm literally back to normal. if someone had told me this was possible a year ago, i wouldn't have believed them, i thought i was going to be babying my arms and counting my keystrokes for the rest of my life. in fact, my physiotherapist told me in no uncertain terms that i'd be dealing with this for the rest of my life.
sarno's theory in a non-medical nutshell: there's nothing wrong with your arms, the pain is caused by limited blood flow to your arms/wrists/fingers. the lack of blood flow is caused by your unconscious. why is your unconscious doing this? to distract you from dealing with painful emotions. why your arms and not your back or something else? your subconscious isn't dumb, and knows what will seem plausible to you. how do you fix it? by understanding that it's happening (not, as you might expect me to say at this point, by dealing with your emotions/stresses through therapy). the last part is what most people seem to get hung up on, and most of sarno's book is trying to convince you that this isn't a crackpot theory.
here's the caveat, which is explicitly discussed in the books as well. sarno thinks most rsi (and other chronic pain) is caused by what he calls tms, but it's possible there is something physically/mechanically wrong with you, so you should see a doctor first to discount this. in my case, i'd already seen several and had conflicting diagnoses and recommended treatments that got me nowhere, so i dove right into the sarno treatment.
here's a couple links that you can read about it in more detail, but seriously, buy the book or get it from
http://aaroniba.net/articles/tmp/how-i-cured-my-rsi-pain.htm...
http://tmswiki.wetpaint.com/page/Repetitive+Strain+Injuries+...
http://podolsky.everybody.org/rsi/