Determine databases specified Login has access to on SQL Azure
-- Run this query on master

SELECT A.name as userName, B.name as login, B.Type_desc, default_database_name, B.* 
FROM sys.sysusers A 
     FULL OUTER JOIN sys.sql_logins B 
     ON A.sid = B.sid
WHERE islogin = 1 and A.sid is not null

-- Run this on user databases

SELECT DB_NAME(DB_ID()) as DatabaseName, *
FROM sys.sysusers