Just enter your email stuff the same as it it with your Outlook or Outlook Express or Whatever e-mail client. Here's the section of php.ini
[mail function]
; For Win32 only.
SMTP = mail.bna.bellsouth.net//whatever your e-mail cliest uses for your email
smtp_port = 25
; For Win32 only.
sendmail_from = youremail address here
My ISP also requires all that but it works fine with my system, as a matter of fact I just used mail() to send an inline attachment to myself to test out a script.