List the members of a Facebook group via API

This is no longer possible:

This edge was deprecated on April 4th, 2018, and can no longer be used.

Yes - use the members connection. Check out the Group reference on the Graph API.

First you need an access token. I'd recommend this article:

http://benbiddington.wordpress.com/2010/04/23/facebook-graph-api-getting-access-tokens/

If you want a permanent access token you must ask for the "offline_access" extended permission on getting it.

After that, it's just a matter of issuing a REST API call:

https://graph.facebook.com/[GROUPID]/members?access_token=[ACCESSTOKEN]

and you'll receive a JSON list of all the members of that group. Very handy!