First Chris Moneymaker does not now nor has he ever made a living at online poker. In fact he has lost thousands.
If you are looking at online poker as a career picking the right game is crucial. Low limit games are diffucult to crack because the rake in these games is generally much more than in B&M simply because of the time it takes to play hands. Professionals (specifically...Dutch Boyd) have said that the rake in online poker is way out of line.
If you want to make a living at online poker....host your own site.