I think the rather long essay by Schegloff in the first volume of "Lectures on conversation" published by Blackwell in 1992 under Sacks authorship is the best source I know. Two interviews by Schegloff also have some information. I have attached the two "interview" articles. Check out the essay in "Lectures"....it is really informative.
Hi Martin, I guess I should directly answer your question...They met as graduate (doctoral) students at Berkeley and then both found themselves working (Schegloff on the UCLA faculty, I think) and Sacks on a research grant for...Garfinkel?.....in Los Angeles....I believe that is the way they met.