It's long since been canceled. I have the whole 5 seasons on DVD though (plus the movies). You may be able to find some episodes on youtube, but you kinda have to watch the series in order, because it's one long story arc from beginning to end.
Indeed. Joe Strazynsky had the whole series planned out, including the first two movies they made, from the time he pitched it to the executives, who couldn't ruin the show no matter how hard they tried.