Don’t have access to Access (ha ha), but stumbled across this and thought some might find it useful: a VBA macro for Microsoft Access that exports a table/query with latitude and longitude to Google Earth’s KML format. The original code has disappeared, but a page that offers explanations and augmentations to the original code can be found here.
Also tucked away in my bookmarks was this link to a Google Earth community post offering an XSL-based tool for exporting from Access to KML. The link to the downloadable file seems to be missing, but I snagged it at the time, and you can download it from this link.
As I said, haven’t tried any of these – use at your own risk/discretion.