I know this probably isn't the right place for this, but I keep losing the link to this site no matter what I try...So since this post is about "getting the most out of" your EP (Pets) I guess it couldn't hurt... This is the link to the site that was mentioned by Frogman sometime after Seasons came out... to anyone else losing their memory and bookmarked sites!
Its to a site where you can download all the Pre-order bonus items for all the sim games so far:
http://ts2downloads.freespaces.com/index.html