I looked into this a while ago and could only came up with the following options:
1) Use the trusted sites in IE and the security policy to only allow trusted sites in IE
2) Use the firewall/ web filter
3) Create a .vbs file that opens an IE instance without menu bars, fixed size etc so that the user just has a simple window in which to work. The downside is that you can use F11 or CTRL-N to view the address bar or create a new instance (also manageable in the policy).
Good luck, and let me know if you find any other options as I still need something which is an improvement on 3.