Here, I got this tidbit off this (sims zone) website:
"With the appearing of the Sims 2 Pets at E3, rumours about the game have sprung up as well. Gaming shop EB Games had the title in their database for several platforms.... but by now all product pages for the 'Sims 2: Pets' have been removed. Although it's not unthinkable that a Sims title for consoles and handhelds is currently in the make, the Sims 2: Pets is more than likely the fourth expansion pack for the PC, considering the full E3 trailer (see TheSidDog.com for a new video, near the bottom of the page) has PC-like graphics.... Naturally we'll keep you up-to-date with all the latest news about upcoming Sims games, but until then it's safest to assume that the Sims 2: Pets is primarily the next PC expansion pack. "
I took a little bit out, but thats mainly the little article thing. but it tells you that it's 'more than likely' to be the next expansion pack, and if you go to www.siddog.com
then you can find a video. hope it helps.