The feature is still in beta because Google has incomplete data about pedestrian pathways. Google Maps advises you to "use caution when walking in unfamiliar areas".
Tip. If you only see driving directions, copy the permalink of the page by clicking on "Link to this page", append &dirflg=w and paste the new URL in the address bar.
As usually with Google Maps directions, you can print them, email them, obtain a permalink that can be bookmarked or embed them in a site. Another option is to save the directions as a custom map: just click on "Link to this page", copy the link, add &output=kml at the end and then create a new map in the My Maps tab by importing the KML file.
Until recently, Ask.com offered walking directions, but the feature is no longer available because Ask.com decided to replace its mapping service with Microsoft Virtual Earth.