The first Orthodox parish I visited, the homily was after the Liturgy and was about 20 minutes. Currently, at my parish, the homily is after the Gospel reading and is usually <15 minutes, on Sundays. Weekday Liturgy may have no homily, unless it's a Feast day. I visit the Greek Church once in while on a weekday and the priest does the homily after the Liturgy, combined with announcements. Then he gives dimissal and distributes antidoron. Longest sermon I ever witnessed was about two and a half hours (just the sermon. Don't count the 3+ hours of holy-rolling and singing) at a Pentecostal revival by evangelist Yiye Avila (kind of like a Billy Graham). If you are Puerto Rican, or at least Hispanic, you know the name and, Good Lord, could the guy preach forever.