Well, if it's a "simple" webpage, not overly complex.....
Notepad.
Seriously. Best to learn on a small project, like a personal page. I use plain old Photoshop to cut up images when needed for banners or buttons or whatever, but I've been coding HTML directly in notepad since probably 1999. The basics are really easy, and you avoid all that bloat/garbage that some editors like Frontpage (or heck, anything Microsoft!) add into the code.