Wikipedia:Policies and guidelines describes how Wikipedia arrives at its policies and guidelines through a process of discussion and consensus. Discussion takes place in the various policy pages which form part of the "Wikipedia:" namespace. Sometimes policy is discussed off-wiki, but decisions always take place on-wiki.
Two words for the same thing. An administrator is simply a volunteerWikipedian who can access some of the few restricted Wikipedia software functions: deleting articles and files, protecting and unprotecting pages, and blocking and unblocking users. The software internally uses the string "sysop" to flag their accounts, a shortened term forsystemoperator. See thecurrent list of administrators.
You must have years of a good edit history that shows you understand Wikipedia policies, have good judgement, a good temperament, and have a need for the administrator toolset. A nomination is then made atWikipedia:Requests for adminship where the community decides if the user deserves the tools. Honestly, you can do 95% of tasks on Wikipedia without being an administrator.
Administrators monitor each other; nearly all admin actions are reversible by any other admin (includingpage deletions,page protections, and blocks). TheArbitration Committee also has the power to sanction administrators, and does so fairly regularly. You can report problems with admins misusing their privileges atWikipedia:Administrators' noticeboard.
Only administrators can unblock IP addresses. To request that an IP address be unblocked, seeWikipedia:Appealing a block and follow the instructions there.
How can I request for an admin to block a user or IP?
