In Windows XP Pro, in addition to an administrator account, I also have a limited account for going online. (Yes, I also take virtually all of the other recommended precautions against malware.)

I want my administrator and limited accounts to be able to share all my documents (as well as my favorites and Desktop items), with the limited account to have the same privileges as my administrator account to create, read, write, edit, save, and delete these documents.

And I would like to apply these requirements not only to documents to be created after I implement this scenario, but also to documents that already exist. And would like the whole implementation to be simple and easy to use.

Maybe I'm just not looking in the right places, but so far I haven't found anything on the net that tells me (clearly, at least) how to do all this as I've just described.

Any suggestions?

Open Windows Explorer.
Go to Tools, Folder Options, View tab.
Deselect "Use simple file sharing"
Select Apply, Ok

Now find the folder that you wish to change permissions on.
Right-click on it, select Properties, Security tab.
Select the Users group (or whatever group your limited accounts belong to) and check Full Control under Permissions for Users.
Select Apply, Ok, and you're done.