Adobe InDesign or Quark!
Everything else is overkill! 😀
On a serious note, keeping it one page is great for people just starting out. And it may be great for certain jobs, but it's not always the case with more experienced job seekers. My resume is two pages, and it was hard to get it DOWN to that.
Keeping it simple and to the point IS always the case though, even with two pages it's a must.