I have clients with Rheumatoid Arthritis. They differ in age, health, muscle tension and massage goals. I don't believe there is one method of massage more effective than others, but massage overall is helpful, because it helps relieve pain, increase flexibility, improve joint range of motion, lower stress hormones and increase endorphins.
During the subacute phase (no areas actively swollen), I massage them the same as other clients (according to their specific goals and needs). When they are in an acute phase (for example, when one hand is hot, red, puffy and swollen to twice its normal size) I completely avoid the swollen areas, but provide gentler massage to the rest of the body. Pathology professionals vary on their advice for massage in the acute phase. Some say that massage is completely contraindicated body-wide; others say that only the swollen areas are contraindicated. I consulted with doctors in my area, and they advocated massage, so long as swollen areas were avoided, so that's what I've chosen to do.
Here's a website with some pretty thorough information on Rheumatoid Arthritis, including conventional and alternative treatments. It's not massage-focused, but packed with other information:
http://www.umm.edu/altmed/ConsConditions/RheumatoidArthritiscc.html