I want to share photos with my family but they don't have accounts on Flickr, is there any feature like Picasa's 'Anyone with the link' in Flickr? so they don't have to create account on Flickr.
Usually photos are public by default in flickr, but if you have set more restrictive permissions, you can go to http://www.flickr.com/photos/organize/, drag the photos you want to share into the the center of the page, then select Permissions->Who can see, tag, comment?
Choose "Anyone (Public)" in the dialog that appears.
There is also the option to create a set and hand out a guest pass to see it.