Hi,
I don't know if you had a look at this but if you still learning (especially about postfix) like I am, then I think this link will help too.
http://www.linuxquestions.org/questions/showthread.php?t=453706
Apart from that, you say that you loaded postfix, when you did the install of your system did it load sendmail by chance?
Some differences that I noticed in your main.cf are:
missing inet_interfaces = all
You are using this, whereas I am using the spooler to deliver prior.
home_mailbox = Maildir/
mail_spool_directory=/var/spool/mail
this delivers the mail to user accounts on the system but if you are going to be using virtual email accounts then I believe that it will do that if you use the virtual file:
virtual_alias_maps = hash:/etc/postfix/virtual
You will probably, if you have not done so, want to check your configuration with:
postfix check
I think that you will want to try re-indexing your aliases.db using the command after issuing:
postfix stop
postalias hash:/etc/postfix/virtual
postfix start
then you will want to check your logs again.
Peter