After doing a great job on jailbreaking iPhone 1.0, we all were waiting for ‘iPhone Dev Team’ jailbreaking iPhone 3G too. And it took only five days after launch.
Anyway, I think much fewer people is going to liberate its iPhone 3G. When first version of iPhone was released it was available only in few markets: USA, UK, Germany, France,… Many people from other unfortunate countries was interested in buying an iPhone, not signing the contract with operators, unlocking it and then using the iPhone with their current SIM - and tariffs- in their country.
Now, iPhone 3G is available much broader over the world and flights to New York for buying and iPhone will stop - specially from Europe.
Moreover - and this is a key point - iPhone 3G is given the end user only when the contract with the mobile carrier is already signed. So, you could unlock your iPhone and use it through your previous operator network, but this will not save you from paying the fees to the operator who sold you the iPhone.
For sure, not many people will be interesting in paying twice for its mobility bill.