Smarterliving.com has a primer on laundering frequent flyer miles from program to program, outlining transfers via Amtrak, Hilton, Diners Club, and Points.com.
It errs in saying that only American and Midwest remain in the Hilton HHonors Reward Exchange among US carriers (Hawaiian participates as well) and it doesn’t draw some of the neat conclusions for you, such as that you can use the Amtrak program as a tool to earn United miles no matter who you fly amongst US carriers (other than America West and Southwest). But it’s a pretty good introduction.
