You actually considered doing it? These sorts of messages practically scream scam. There are probably easier, cheaper and faster ways of getting a used laptop than that. And it's not like when a laptop goes up on a bidding site and everyone swarms it. Plenty of people sell laptops through such things.
I'm selling the laptop. He contacted me to buy it.
My friend who works at the Better Business Bureau tells me that the way this works is that it's possible to send you temporary money in Paypal which can expire after a time period. I have no clue how this is done though. So I bet it's either that or phishing.
He's paying you, correct? If that's the case, I don't know how he could scam you. 'Temporary money'? Please. If you mean, 'pay with credit card then lie and tell your company that you didn't authorize the payment' that might be possible, but I'm pretty sure that's more than a little illegal.
You could set up a seperate paypal account (that is, one not linked to your bank account/credit card) and get him to pay into that, then don't actually send him the laptop. No one would pay $250 (plus the actual price of it) to ship a second-hand laptop overseas -- if he would, then he's clearly got money to burn anyway so it's a victimless crime, so to speak.
No real danger.
Also, as for the phishing scheme? Just don't click on any of his links, I guess? Since he's the one paying you, he's the one that should be depositing money, after all.