If you have created your site using Wordpress and are experiencing high load or CPU issues we recommend you have a read of the Wordpress forums http://en.forums.wordpress.com. These forums contain numerous bits of advice from others who have similar issues with Wordpress installations.

Other specific examples:

http://www.wpbuster.com/hosting/how-to-reduce-wordpress-server-load-on-shared-hosting

http://codex.wordpress.org/High_Traffic_Tips_For_WordPress

Other suggestions:

Installing http://wordpress.org/extend/plugins/wp-super-cache/ can often reduce your CPU and is a good place to start.

If you believe your account was hacked:

http://codex.wordpress.org/Hardening_WordPress