Just a quick tip to anyone hosting their own wordpress installation. If you run wordpress on a linux installation the chances are you already have fail2ban running. In case you do not have it, go ahead and install it right away to get a better secured environment!
For wordpress there is a plugin called WP Fail2Ban. This plugin writes all the login attempts to SYSLOG where fail2ban can act apon it. The plugin comes with a preconfigured filter that you can use in fail2ban.
From the installation on, anyone who tries to gain access to your installation will be banned after 3 attempts (default configuration). Yay for security!