How do I change my permissions?

[Katherine Keller]

Okay, I thought I'd start playing around with YUM and installing some
software and such.  After going to the YDL page and reading up on what
to do with YUM I opened the terminal and tried both

yum list & YUM list

The cthulu speech that followed said:  


Gathering package information from servers
Getting headers from: Yellow Dog Linux 3.0 base
Traceback (most recent call last):
  File "/usr/bin/yum", line 44, in ?
    yummain.main(sys.argv[1:])
  File "yummain.py", line 141, in main
  File "clientStuff.py", line 643, in get_package_info_from_servers
OSError: [Errno 13] Permission denied: '/var/cache/yum/base'


Is this something to do with my not having the right permissions when
logged in on my every day account?  I've been poking around in the
various menus, but can't find anything that will let me change the
permissions I have on my every day account.

How do I set myself up so that I have the kind of privlidges I have when
running OSX?  Where I can do anything but muck around with the files
owned by root?

Thanks,

Katherine
PS. Preferably from the GUI, not the CLI.