Won't work with IE6 browsers, but here's how WordPress users do it.
http://perfectionlabstips.wordpress.com/2008/12/30/serving-gzipped-gz-files-as-compressed-css-javascript-html-content/
Their examples are for CSS and JavaScript, but it's easily applicable for .html from the samples.
They show you how to detect for browsers that won't work and keep an uncompressed copy and compressed copy side by side so your site will work with unsupportive browsers.
The following rule detects if the browser supports gzip, checks to see if you have a .gz file of the same name as the requested file and serves it instead of the uncompressed file:
RewriteCond %{HTTP:Accept-Encoding} gzip
RewriteCond %{REQUEST_FILENAME}.gz -f
RewriteRule ^(.*)$ $1.gz [L]