Creating and organizing user accounts

Hi,
I'm brand new to the forum and have a question on setting up user accounts. I own an Imac running 10.6.7. About a month ago I needed to set up a user account with parental controls for my 10 year old son. I couldn't find good documentation on how to do this and had lots of trouble. The account I set up from scratch didn't work (the preferences I set for the applications and widgets wouldn't hold and I couldn't link up to my Firefox ad-ons (they have a great script for blocking comments on sites such as you tube). I ended up creating a new admin account for myself and changing my existing account to have parental controls. Now I have these problems:
1) I don't know how to link the applications between the two accounts. All of my photos, music and rapidweaver items reside in my sons account (as does all of my email sent prior to the switch).
2) My Firefox and Thunderbird (which I had to reinstall on my account) won't connect to download updates (all other internet connections seem ok).
3) I just got a notice that I have apple updates (I haven't downloaded because they require a restart). If they connect and update on my account, do I have to run them on my son's?
4) Some of the widgets I give my son access to still revert back to no access with each restart.
Is there anyway to set these accounts up to share some of the applications and updates?
Thanks!!

1. Use the 'Shared' folder to share documents between accounts on the same computer.
2. You may need admin rights to download updates. e.g. \Users\allye\shared.
3. No, they apply to the applications which are not user account specific, once installed, they apply to everyone.
4. You may need to give read permissions to access them