Google Mail or Gmail can be opened in web browser at the location http://www.gmail.com and it will open up the  page for Google account login.

You can access the page but if the domain gmail.com is blocked then you can alternatively open http://mail.google.com and it will point you to same page to log into your google account.

By Logging into your google account you can check your emails.

Second option would be to open up the Igoogle page where you can add a widget of gmail which will help you to load the gmail in a small window. With this you can even chat with your friends.