2 one business, and one personal. it is in the terms and conditions.

Thanks OWG

I thought so, but some have more then 2 and I don't think it is difficult to setup more then 2 either.

You can set up more, same as you cans et up multiple adsense accounts. BUT you start putting big money through there and they arelikely to close it down!

I only have the one account at the moment. The ability to add more email addresses associated with the account helps if you have different sites which require different addresses. (Take the LBS Sites as examples).