Splash Page Login vs. Join......

How to modify the Splash Page? Specifically I want to replace the default JOIN form with the actual LOGIN form. My users find it a bit disconcerning that when they thi8nk they are logging into the system from the splash page, they are presented with another login page and feel they are forced to do it twice, as if the first form did not 'take'. Is it possible to switch these two forms, so they can actually login from splash, but also have the button to go to the JOIN page instead of the button for LOGIN...?