With last week's launch of Google SMS, the world's most popular search platform made a big entrance into the mobile space. The Google SMS service is limited to only a handful functions at this time, but MobileTracker believes the service will expand to driving directions in the near future.
Users of the service have reported getting messages back for queries with no results containing the text, "Looking for driving directions? Unforntunately this feature is not yet supported." A wishful hint or soon to be feature? This message can be reproduced by texting 46645 (GOOGL on most phones) the message "directions".
Don't hold out for the new feature though--Google is known for working at its own pace. Google News is still in beta even though it is over two years old and Gmail and Orkut are both still invite only services.