Google, by way of Labs, has recently begun offering previews of Google Maps in Gmail and Buzz. In other words, you can now see a preview of the map right inline with your email message.
The new functionality does need to be enabled, however that is simple enough. In Gmail, just click on Settings -> Labs and then enable “Google Maps previews in mail” and then click the “Save Changes” button at the bottom.
Once that is complete you will have a map preview for any address found in your email messages. The one catch here is that at the moment this will only work for a US based address.
Read [Official Gmail Blog]