blogs MU login link at the top not working

Hello
I have my site installed at http://selfhelpblogs.org and there is a link on the header for "login".
the problem is that when clicked it takes users to the admin blog instead of a login page.
how do I fix that?
please use detailed explanation since I am not a developer, please tell me what to change and where so I know what to do.
Thank you so much in advance.