If you go to Tools > Options > and then select the tab marked Mail format, you should be able to set signatures on each account from there. You'll see at the bottom of that page that there is a section marked Signatures. Below that, you should see "Select signatures for account:" with a drop-down box next to it. You can choose which account you'd like, and then select which signature you'd like for new mail or for replies and forwards on that account. If you don't yet have a signature, you can click on the Signatures button and set one up from there. I have Outlook 2003 with 3 accounts set up, and this works for me.