| The biggest pitfall when buying from an overseas seller is currency exchange. If the seller doesn't use PayPal, and insists on their currency, you can take a big hit on exchange rates and fees.
And of course accountability. If you send money overseas and get nothing in return, enforcement is kinda tough. You can use an escrow service if you're nervous (see escrow.com as an example). Escrow is where you use a third party to hold the money until the sale is completed satisfactorily.
As a seller, it's common for those hassles to fall on the buyer, so you're pretty safe there. But when shipping something overseas, you have to fill out some extra forms, like the customs declaration. The buyer might want you to put particular information on that form so it makes things easier for them, but I haven't run into that yet. Overseas sellers always mark the stuff they're sending me as "gift" -- I think that reduces the chance the item will be treated as commercial and thus get taxed extra?
Cheers!
ltt | 
Pitfalls of selling overseas ??? 
