Hi, Michael; your setup will remain the same, just take on the look of your vBulletin setup when you do the conversion. When you get ready to make the change, you'll need to update the vbversion variable in your settings table to 'vb3' to tell PhotoPost you've switched.
Be sure you are running a current release of PhotoPost first, just to be sure you have everything ready.
Please do not PM me for support or sales questions. Thank you for your understanding.