I solved the errors thing - just had to make sure to insert [General] before my mail subject line (is there a way to automatically set what category they'll go into?) but my posts are being made without an author being listed, which is breaking the navigation in my blog.
This is wicked - thanks very much for doing this. I set this up for my blog and the mail sending and checking via wp-mail.php seem to go fine, however, if I try to check my blog, I get the same post over and over and over again, even if it was only posted once. What's up with that?