Make a 7.x-1.1 release of this module.

The permissions are not available unless you change the function name from tweetmeme_perm to tweetmeme_permission in the file tweetmeme.module (line 31). Without the ability to configure permissions, the retweet widget will not appear unless you are logged in as user 1. After making the change, you can go to the Permissions page in D7 and provide access to the module to the appropriate roles.