It looks like they'll start shipping on October 19th and if history is any indication, they'll be sold out from the minute they are available. Those that order right away reserve a place in line (and if you don't pay for 2nd day or overnight delivery, even that place will probably be a week after launch). Here's the big difference for those looking at the US versus the International units. Both have:
3G Wireless: 3G wireless lets you download books right from your Kindle; no annual contracts, no monthly fees, and no hunting for Wi-Fi hotspots
International Coverage: Enjoy 3G wireless coverage at home or abroad in over 100 countries
When traveling abroad, you can download books wirelessly from the Kindle Store or your Archived Items for a fee of $1.99Cell coverage for this Kindle is via AT&T, not Sprint, so that may mean a much lower coverage area inside the US (especially if you believe those Verizon ads running these days). So those outside the US will still want to mainly use their USB cable, but now have a cellular option. There is still no wi-fi, which will no doubt lower their technical support costs, since connecting to a hotspot can be tricky. Adding this option might be their next evolution and it's one that international customers (and US with poor cell coverage) would welcome, at least for those savvy enough to be able to hook up to their home networks and the free hotspots that are starting to blanket the world (and every bookstore, now that Borders has joined Barnes and Noble and Books-A-Million in giving away wi-fi to promote ebook sales on the new Sony units they'll be selling this year).
The only other change that I could see was that the 2-year extended warranty sold by Amazon is for US customers only (but works on either Kindle, just only inside the US), while those outside the US (and yes, you can order one and have it shipped anywhere) get the same one-year warranty as any other Kindle customer.
The price on the US version of the Kindle, in the meantime, is $259, with refurbished units at $219 (those $199 units went fast). It looks as though they still have to be shipped to a US address, but if you don't want to risk that $2/book wireless fee, they are still a good option even for international customers or those that travel. On the other hand, if you are out of the country often and must download those books while trapped in yet another airport, the international version will provide more entertainment, almost instantly, for as little as two bucks - a deal which can't be beat, in that situation.