it's already there in mine.... When i goto Reffering Source, i get: google[organic] (direct)[(none)] msn[organic] yahoo[organic] etc
I have seen web analytics firms offering this as a service, so I know it's possible, just dont think it's that easy to implement, which is a bummer.
Are you sure you are getting traffic from other search engines? GA should show all domains that refer traffic to your site.