Publish to HTML cache

Hi,

I want to store WordPress produced pages in a cache on my local server. The cache should be served to visitors instead of the direct-from-database version WordPress usually serves.

I need this to cut hosting costs. I do also thinks it would signifigantly improve page loading times.

Is there a plug-in that can produce HTML pages, and keep them up to date? (The cache would have to be updated when users post comments, I publish a new post, or I chagne the blogtheme. Preferably selecrtive HTML documents only.)