"A recent lengthy discussion in the Interaction Design Association focused on the placement of actions in Web forms that span several Web pages. The quintessential question underlying this debate is: can an action which leads people to the previous step of a process be placed to the right of an action that leads users to the next step of a process?
One side of the debate argues that there is a natural organization: actions that move you forward are on the right, actions that move you backward are on the left (in places where people read from left to right). The other side argues that the notion of “primary” actions (those that move people forward) outweigh this consideration and “secondary” actions (which are much less used) can be placed to the right of primary actions even if they allow people to access previous steps. The presence of a prominent primary action in the “line of fire” of people filling a Web form, allows them to land on the action they need to take as they finish answering the questions a form requires. For the sake of clarity, I illustrated this in the image below.
So who is right? Both sides are." (Continued via Functioning Form, LukeW) [Usability Resources]