You need to be friends with the Leader of the pack first. In case you didn't know, the leader is the wolf with glowing yellow eyes. Just get the relationship high enough, and make it bite you. Then you'll transform into a werewolf and stay like that at night. During daytime, you'll be a normal sim. Hope that helps

you need the sims 2 pets , and here's a video to help ;)
Hope u know now :D ^__^

if you want to do it legitly plant tons of pine trees
around your sims house.even the cheat takes a
while at times.you type the main cheat code then
hold the shift key and click the mailbox then click
leader of the pack and hell appear.