My Applications folder is missing (Mac OS X 10.5.6)

Gone from where? The HD? The sidebar of a Finder window? The Dock? The Desktop?

Do you have a backup of your system?

Are you sure it is gone and did just go hidden? Go into Terminal, and type in *ls -a /*
Do you see and applications folder?

You could try opening up Finder preferences, select the Sidebar button at the top and deselect 'Applications' from the Places section then reselect it. That may help. If it doesn't help, open a new Finder window and go to the top level of your HD (Macintosh HD?) You should see the Applications folder there so just drag it to where it used to be in the sidebar.

No problem 🙂