I have enabled support for the Tehnoetic freedom-respecting WiFi adapters
(N150 and N150HGA) in Replicant 4.2.
http://redmine.replicant.us/boards/33/topics/11763?r=13395#message-13395
My patches are not yet merged in the official image, but prebuilt Replicant
4.2 images with external WiFi support are available for both S2 and S3.
https://wiki.tehnoetic.com/doku.php?id=tehnoetic_wifi_replicant
Fil has written better scripts to make it easier for users to connect to WiFi
http://redmine.replicant.us/boards/9/topics/13932
And Wolfgang has recently enabled the external WiFi support in Replicant 6.0
which is not officially released either.
https://redmine.replicant.us/boards/21/topics/14009?r=14032