For those of you who have picked up Windows 7 already, you may have noticed that you can't pin Windows Update to the start menu as you could in Vista. However, I've found a couple sites that mention ways to quickly access Windows Update regardless. HowToGeek.com mentions a way to actually pin Windows Update to the taskbar, if that's your kind of thing.
However, I prefer the "no tweak needed" access mentioned by a fellow Blogger on Cool Thing of the Day, who mentions you can pull up Windows Update with just two clicks. Just right click the Action Center (flag) icon on the right side of the taskbar, and "Open Windows Update" will be the bottom option! A nice, clean, easy way to access Windows Update compared to the start menu, especially if you've cluttered it with a lot of programs.