I'm planning a site that is 780px wide by 460px high that is top centered in the browser. I want to have mouse over events that hide/show indepth info. I was planning on using layers and use hide/show but the positioning will be weird in different browsers/monitors. How could I set this up?

not sure, wouldn't want to venture without actually knowing anything abut your site. To be honest, when it comes to browser inconsistency, its a trial and error thing.

Btw, i don't THINK there should be any inconsistencies, but if you do come accross any, give a link so that i can see it in action