On the website, go to their SparkPage and click the Feed button there. If they have enabled it to be shared, you will see it there.
If you are looking for your Friend Feed that shows the feed info for all your mutual friends, go to your Start page and click the "Friend Feed" link that is on the right side under the "My Community Quick Links" heading.
I hope this helps!
"I am only one, but I am one. I cannot do everything, but I can do something. And I will not let what I cannot do interfere with what I can do." Edward Everett Hale