SELECT permission is given to USER not to LOGIN . so first you shiuld have LOGIN which will act as USER on any
database where you want to set this permission
for login creation
CREATE LOGIN sam
WITH PASSWORD = '340$Uuxwp7Mcxo7Khy';
You can use Create USer to create a user
USE AdventureWorks;
CREATE USER sam FOR LOGIN sam;
and to Grant (Read-only access) you can use the following
GRANT SELECT TO sam
Hope that helps.
-------Bhuvnesh----------
I work only to learn Sql Server...though my company pays me for getting their stuff done;-)