That IS quite a long time for an item to come through from the US.
Can you track the package's progress at all using the number from the Registered Mail receipt on the USPS website?
That should show whether it's left US shores or not for starters ....

The other thing you can do it use the same tracking number on the Royal Mail website -
www.royalmail.com US Mail no longer shows when it left the US (I doublechecked at the post office TWICE since I sent it) - only when it was accepted at the post office.
I was shocked to find out that Royal Mail would trace it, so I tried and nope...
Got this message "This item was posted from overseas and can't be tracked by Track and Trace."
With that value on it and the fact it's Registered will probably mean the person you sent it to will have to pay Duty on it to receive it I'm afraid, so don't be surprised if you get more grief from them because of it.

Well, they chose to have it sent Registered, so I'm afraid I'll have little sympathy. The value IS less than $50 US (pretty sure it's $45), so I'd be very shocked if he had to pay duty on it... I suggested it be sent by Global Priority Mail, but he wanted some insurance on it and since Registered Mail covers the amount he wanted, that's what he chose.
I very much doubt the buyer will want to make any kind of enquiries with the Customs Office for fear of attracting too much attention to whatever it is they've bought from you, which is another reason you're getting so much heat from them!
Well, my next advice to him will be to check with his local post office and inquire with Customs...
There's the possibility that it could've gone by surface mail instead - I assume you sent it Airmail? - which is the main reason I asked you to track it on the USPS site was to see if it had actually been sent!
Lord, I hope it didn't! I NEVER send ANYTHING via surface mail. All packages I send overseas have a blue Air Mail sticker on it and the post office typically stamps it "Air Mail" as well.
And I've checked once a week with the USPS online tracking - always get the same information which shows the time & date it was accepted at my local post office.
I had a similar experience quite recently (though my package wasn't sent Registered)
Glad it turned up! Stupid mail systems!
I appreciate the suggestions and the story

Anyone else have a package that took forever to get to them?