postfix configuration for multiple domains

I use postfix for sending mail from the server but google for all receiving/imap etc. To get something similar to google on a linode you need an email server i.e. exim, postfix etc, something for imap, i.e. courier or dovcot, and a webmail client (there's an abundance of those). On top of that you'll need anti spam (spam assassin is common) and anti virus (clam av). That's quite a lot on one machine and a lot to administer.

> I will be learning this stuff for the first time

Use Google. Let them deal with the administration. I've been using them for email for about 4 years now. Absolutely no problems at all and I've not had to deal with or worry about anything. Leaving me with time to deal with other stuff that's way more important.