It's available now, although you won't yet find it in the list of Google services and tools, nor on the Google labs page.
As well as sharing with your friends, the new bookmarklet allows you to share your links via several third-party sites, including Facebook, digg, reddit and del.icio.us.
In itself, it wouldn't be worldshaking; but
- It's from Google
- There are rumors of a soon-to-be-released Google api for social networking.