It seems that mail on my server is functional -- kind of. I have a simple PHP mailer script that is capable of mailing any email address that is not local. e.g [email protected]

However, if I try [email protected], it tells me

/home/myuser/dead.letter... Saved message in /home/myuser/dead.letter

and sometimes

You have new mail. 

What does this mean? Does anyone know what I can do to make my emails actually go through?

I'm using google apps for domains -- so basically gmail is hosting my domain's email and I'm not using my own servers for receiving mail. I've set up the nameservers correctly -- I wonder if it's got to do with my sending configuration (what does PHP's mail function normally send with anyway, sendmail?) or maybe it's my receiving configuration -- maybe something makes it act differently for "local" mail