How to see my site again

Sry for the stupid question but I am new about Drupal and LAMP system...anyway that's my problem...

I logged in my Drupal site as administrator(think so)...
I was setting my site properties...and I choosed to set the site off for maintenance....then i logged out....
Now I can't see my own Drupal site homepage anymore....i can only see the drupal page displaying : the site is offline for maintenance

anyone know a way to set things as before? must I have to set some fields in drupal database tables to set maintenance out?

If you know...pls tell me! I'm freezed by this thing,thanks!!!