Paul,
I usually state that I will only ship within the 
US out of convenience.  Even shipping to 
neighboring Canada requires extra time and expense 
(like customs forms).  Int'l shipping also means 
that your rates will vary and makes it a lot 
harder to ballpark a figure.  You also take a 
greater risk with overseas shipping, AND a longer 
turnaround for payment and such.

Is that enough?  ^_^

Here's the catch:  If someone asks nicely, I have 
always accomdodated overseas shipping.  But they 
have to ask (thereby demonstrating friendliness 
and initiative---nothing worse than a 
procrastinating, uncommunicative, unfriendly 
overseas buyer!).  In my early Ebay days, I would 
often allow overseas shipping in my auctions, and 
it seemed like I would attract some VERY flaky 
buyers from other countries who wanted to haggle 
AFTER the deal was closed.  Not fun at all.

Still, these are just my personal experiences.

I think any decent seller who still provides 
customer service (not one of these impersonal 
Ebay-Machines that runs 1,000 auctions at a time 
and won't respond to e-mail) will gladly ship 
overseas if you ask.

I hope shipping issues never keep you from a prize 
cel!

JP