two websites, one home page

Hi

I have two WP wwebsites in different folders on the same server. I need a splash page that can send visitors to either site. How do I do this?

My current solution is an .html pag that sends folks to the left or right: http://www.thomaskaufman.com, which takes you either to http://www.thomaskaufman.com/dp or http://www.thomaskaufman.com/author.

But I made this page in Dreamweaver long ago, it’s not very cool-looking. So how can I make a page like this in WP?

If I try pasting the code into WP, it looks like this:
http://thomaskaufman.com/author/splitter/

thanks