Use the WP SuperCache plugin - I was always getting my hosting acocunt suspended cos I was using more than my allocated CPU % - after adding this plugin and setting it up, my CPU useage came down drastically - to the point where I could add another 10 autoblogs before it came close to max CPU use agian - it really makes a huge difference. Can't give you the link cos I can't paste URLs yet, but you will find it on the main wordpress site under plugins >> wp super cache