@font-face {
    font-family: DeliciousRoman;
    src: url(http://www.font-face.com/fonts/delicious/Delicious-Roman.otf);
    font-weight:400;
}

Then just use it like any other font in any other style rule.

p {
    font-family: DeliciousRoman, Helvetica, Arial, sans-serif;
}