Yeah, I just made a basic HTML page, which I keep in my home folder. To set it in Firefox, open settings and change the homepage from "Firefox Home" to "Custom...", then enter the path into the box underneath. If you're using a local file like I am, remember to put file:/// at the start of the URL. The process is similar in SpiderWeb, which is my browser on OS X.
Custom homepage and, then, there is an option to open your home page instead of a new tab... I think that is how you do it, but I haven't looked at this in a while.