I have a list where users can create and see their own items, but not other users' items. I, being the site owner, can see all items. How can I give specific users within a Sharepoint Group the ability to see all the list items as well?
I'm assuming in the list's Advanced Settings page you set "Specify which items users can read" to "Only their own".
You need at least the "Manage Lists" permission which is present in the following roles by default:
So... a user would need at least the "Manage Hierarchy" role set in the list's permissions.