You can use ''id'':
$ id eduardomozart
uid=3000011(NETHOUSE\eduardomozart) gid=100(users) grupos=100(users),3000011(NETHOUSE\eduardomozart),3000005(NETHOUSE\domain admins),3000002(NETHOUSE\denied rodc password replication group),3000002(NETHOUSE\denied rodc password replication group),3000009(NETHOUSE\dimension-e521$),3000000(BUILTIN\administrators)
Notice that for idmap_ad backend, the user need to have the attributes uidNumber and gidNumber set at LDAP (Unix Attributes tab from Active Directory User and Computers) as RFC2307 or the command will return "id: eduardomozart: no such user".
Reference: Gerald Carter, Jay Ts, Robert Eckstein, 2007. Using Samba: A File & Print Server for Linux, Unix & Mac OS X. (3rd Edition). O'Reilly, ISBN 0-596-00769-8.