Google has just announced Salesforce.com for Google Apps. This is something that I'm really excited about because we use Salesforce.com as our CRM system and we also work with several large enterprise clients to integrate their web marketing with their Salesforce.com CRM system. Since migrating all my email, calendar and documents over to Google Apps in the last two months I've looked for a way to attach gmail emails to Salesforce contacts but there was only talk about it on the SFDC feature requests boards. I guess they were keeping this one quite until today.
Here's a quick look at how each of the main Google Apps applications will integrate with Salesforce.com
Now I'll just need to keep an eye on the Salesforce.com module for Drupal so we can integrate Drupal applications into Salesforce.com as well.