To Assign users to be admins for specific site or list do the following
1. Login to the system with administrator user “sysadmin”
2. Open site actions menu > site sittings > people and groups
3. Select New> New Group
4. Type the name of the group and under “Give Group Permission to this Site” select “Read - Can view only.”
5. Click create
6. Go to the site that you need to create the permission on it
7. Open site actions menu > site sittings > people and groups
8. Click from the left navigation “site permissions”
9. You will find list of all the groups listed on the page
10. From the top select actions > Edit permissions
11. Click ok for the message that will prompt
12. The page will has checkbox beside each group
13. check the created group
14. and from the top action menu select edit user permissions
15. uncheck the read and check full control
16. click ok
17. add the users under this group