Granting Permissions to User To Access Database

I recently installed Postgres on my server to rid of the horrible
limitations of Mysql. However I am having some trouble setting up
permissions as they are in MySQL.

In MySQL you can grant a user select permissions to all tables in a database
with the command "GRANT select on db.* to .....". Is there a similar way to
accomplish this in Postgres? Reading up on GRANT I see that it only works
for individual tables and not a full database.

As well, how can I restrict a user to only one database. In pg_hba.conf
there is nothing that specifies the user name. I can grant access to the
database to all users on an ip, but I can't grant it to only one user.

Thanks in advance,

Kevin