yes, unless you get those extra custom made skin which allows 3g sim to be used...

for me i chose ipod touch instead of iphone because i intend to use it as a netbook when i want to go travelling overseas. Its quite troublesome when you keep using your iphone and the battery dies, and if you're in trouble or need some help you cant use your phone.
Depending on where you travel, nowadays wifi is pretty common in cafes/complex/hotel/motel so it shouldn't be a big problem getting wifi (especially with starbucks breeding everywhere    )

If you just want to upload pics/vids to your blog then ipod touch would be good enough, don't expect to print out pictures hoping for quality wise... ipod is afterall 2x cheaper than iphone. For serious pics i would rather use a digi cam/dslr instead of any phone anyway...

and its also dam expensive using 3g data overseas, dont see a point in getting an iphone4 just for that. I know a couple of people who didn't turn their 3g off overseas, any the only data they used unintentionally were the mails sent to their inbox. One of them had a bill expense of rm4k+ and the other nearly rm1k 

well something like that, atm apple peel 520 doesn't have 3g connection, but u get to make calls and sms on it.
other skins like sprint u can use it for 3g but no calls/sms

spiderwick - too bad ur not gonna be there for 2 yrs, could get iphone 4 for free in a 2 yr contract!! just pay a min of aus$58 per month which includes calls/sms etc