YoVille will NEVER ask for your password, so please be wary of malicious emails and/or forum posts that request your password, including via web links.
There is a tutorial here viewtopic.php?f=7&t=5512 I had that same question the other day. After you follow those steps you just paste the link in your profile. Go to User Control Panel. Click the tab for Edit Profile. Paste the link where it says, 'Website:'. The link will then show up like a small globe icon under your avatar on the left.