Yes Zen, all the previous seasons ( up to 4 out of 5) are available on dvd now.
http://www.amazon.com/gp/product/B0000E2PVR/qid=1149343416/sr=1-4/ref=sr_1_4/102-9281116-2804933?s=dvd&v=glance&n=130
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"Some say I'm lazy and others say that is just me. Some say I'm crazy, I guess I'll always be"