Finding a great deal in another country is wonderful if you know what you're up against in purchasing it and receiving it.

I often search for rare items in Europe as there seem to be a lot of Italian automotive parts all over the continent -- parts that are simply unavailable in the USA.  Here is what I suggest:

1. Make sure you give yourself enough time to email the seller ahead of time so you can determine if they are willing to ship to the USA.
2. Many Europeans know some English, but many don't.  If they don't reply, it might be because they don't speak English.  Likewise, their English may be as good as 5th grade US English, as they don't get to use it much.  In any case, get out your phrase book and be careful.  Find a friend who speaks their language.  As a last resort, use Babelfish (http://babelfish.altavista.net) to help translate.
3. Understand that international shipping is often a LOT more expensive than domestic shipping.  Also, shipping from one country may be significantly different for the same item.  For instance, I ordered an item from Germany, then an almost identical item from Netherlands (Holland).  The price for the shipping from Netherlands was about 3 times the price from Germany.  This is because the German post office is owned by DHL which uses their own flights into the US.  DutchPost is government owned and they must pay another company to transport their mail to the US -- as a result, sending packages from Germany to the USA is far cheaper.
4. Many Europeans won't take PayPal.  This is because in Europe, bank transfers are very commonplace -- Europeans can transfer money directly to each other free of charge.  They don't set up PayPal accounts because they don't want to pay the exorbitant fees to receive money.   One thing you can do is offer to pay the PayPal fees if you really want the item -- I've found that some sellers will set up an account if you will do that even if their auction says no PayPal.
   
5. Get a contact phone number and call them to verify information.  This may seem like a lot, but if they speak English, it can be very helpful.
   
6. CHECK FEEDBACK and length of time on Ebay!  The longer the better.
   

In my experience, I have bought from multiple countries: Italy, Germany, Spain, France, Belgium, Netherlands and England; and I've been pretty lucky.  I use American Express traveler's cheques to send when the seller doesn't use PayPal, and this has worked out pretty well.  They give some security because they can be refunded if lost.  They cost more, but the security is worth it.

If you take the time and do your homework, and use a LOT of patience, you can find some great deals internationally.  There is risk:  if you don't speak their language, and they don't speak English, you can easily have a misunderstanding.  Be prepared for this risk.  Keep track of whom you've bought from and check them again later if the sale went well.  Repeat purchases are a good way to ensure continued satisfaction.

In the instance you get shafted, your options are few.  You can open a dispute with Ebay, but as we all know that's not very useful to get your money back.  If you send the payment via PayPal and the seller has a verified account, you have some additional protection, but be mindful that PayPal limits complaints to 45 days and shipping from Europe (if you get the "economy" type) can take as much as 6-8 weeks!

The best advice for international bidding is the same as domestic:  know your seller, ask a lot of questions and use the safest payment method possible.

good luck!