Is everyone using Leopard or something? I can't get into any (or even see any ) of my files using another account and I am using Tiger. If that is the case then Apple really needed to restrict spotlight to what is should be able to access.
I made a file named "secret text" using normal account, then logged in with an admin. Spotlight did not find that file. If you have this problem it hast to do with the Folder/file permissions having wrong settings inside your home folder!
I am using a "normal" account on daily basis and my folders inside my home directory exept "Public" and "Share" have permissions
me=read and write
everyone = no access
So, you should check your permissions !
Also use the "apply to eclosed items" function so every file inside your documents, Pictures etc are flagged too !