QUOTE(jynxNdragnfly @ Jul 25 2007, 05:24 PM)

Well my husband is sending off the paperwork tomorrow for the CR-1 so I will officially be joining the 'immigration circus' then.
My quick question is this:
Is USPS the only postal service that will deliver overnight to PO Boxes? We have to send it off to Nebraska and my husband went to do it today only to find out that UPS won't deliver to PO Boxes and it of course it has to go over night since I don't want to pay the 'new and improved' fee for a postmark after July 30.
Any help is much appreciated

From what I've read that is correct, only USPS.
The postmark occurs in the country of origin. Are you mailing from Canada? If so I would recommend express-post. I believe it's 2-5 days. However, as mentioned the post mark will be the Canadian mailing date.