That depends on when it is shown here and in the states. For instance, series 3 started in Australia on 20 Sept and has been on every Monday night since. We were without new episodes of SP from around February though until then.
Another factor is that SP is on Australia's mutlicultural (government owned, supposedly non commercial) TV station SBS (the smallest one) and is the station's top show (or very close to it). Mainly shows like Deep Space Nine etc etc etc are on commercial TV, which has so much in reserve, where SBS doesn't.
At the moment, the new episode shows at 2030-2100 Sydney time (last episode on Monday last was Starvin' Marvin in Space) with a repeated episode (so far in original order) shown straight after (last episode was "Cartman's Mum Is A Dirty Slut") between 2100-2130 Sydney time.
Pay TV network Foxtel also shows SP on thecomedychannel a few times a week but I don't have it (so I don't know where they are up to). For much of this year, Foxtel was the only place to see SP on TV but SBS has the rights to show the new episodes first. When SP first started, the commercial networks (7,9,10) and non commercial government station ABC did not want the rights but changed their minds when renewal time came around but Comedy Central stuck with SBS.
Hope this helps.
On my website www.erk.au.com is a complete list of episodes shown in Australia so far...........
Eric www.erk.au.com "I'm not fat, I'm festively plump!"
premiered here in the US.