The Apple Finder doesn't really offer a good way to do this.
If the shortcoming annoys you enough to spend 35 dollars, Path Finder cures that and many other Finder problems. They do give you a three week trial to decide if it's worth the money or not.
Maybe select the window you want this to occur in, press COMMAND-J to invoke the View Options (also accessible from the View menu) and Keep Items Arranged by Kind rather than Name.
The sort by kind thing is observed in icon view with cmd-J as above, independently in the list view by clicking on the column, and not at all in column view And none of those really put folders first
It's amazing that Apple haven't addressed so many simple things. If they are averse to "magic" sort ordering, at least they could offer a tree-only view in the shelf area or something like that.
I thought I'd never miss XP... There's no OS X solution, so I added the '*' character in front of all the folder names. Now they're at the top of the Finder window.
Nice method that. If you don't want asterisks cluttering up your folder names, maybe use a SPACE instead. It has the same effect.
As a side note, I used to get annoyed by this when I first switched back but now XP's default method annoys me. I guess it's just a case of getting used to it.