With SharePoint it is possible to go beyond the out-of-the-box permission levels that are given.  Perhaps you like the out-of-the-box permission level known as “Contribute”; however you wish you could restrict 1 or 2 things that this permission level allows.  The simplest solution is creating your own permission level for certain users to be associated with.

In MOSS, go to Site Actions >> Site Settings.

Select People and Groups under the Users and Permissions column.

On the next screen, click Site Permissions on the left Quick Launch bar.

Next, under the settings drop down, choose Permission Levels.

Then Click Add a Permission Level.

Now you are on the Add a Permission Level screen.  You have the opportunity to select certain permissions for this new permission level.  You might come across the scenario that when you check a box, other boxes are immediately checked for you.  For example, if you select “Create Groups” under Site Permissions…..”View Pages”, “Browse User Information”, and “Open” are immediately chosen for you.  SharePoint is making it easier on you by letting you know that these permissions will also be needed for the “Create Groups” selection.  When you are finished naming, writing a description of the permission level and selecting the permissions desired, just click the Create button at the bottom.

The screen will go back to the previous Permission Levels screen and your new Permission Level will appear in the list!