Buying an iPhone 3G is taking longer than it took to buy the original iPhone, at least initially. In the Flatiron Crossing Apple Store in Broomfield, CO, where the lines got even longer after the store’s opening, the first transaction was completed in 26 minutes, compared to only a few minutes it took across the country when the original iPhone went on sale in June of 2007.

The big difference, of course, is that customers took the original iPhone home and signed up with AT&T in the comfort of their own homes. With iPhone 3G, Apple is handling the signup or transfer to a new iPhone 3G in the stores, which is, in part, an effort to keep iPhone 3G units from being unlocked and taken to other carrier services that aren’t paying Apple any subsidies.

In addition to that major change in how iPhone 3G units are being processed, such issues as server slowdowns associated with the initial crush of new customers and other unexpected glitches are to be expected.

We should add that transaction times immediately began to improve at our on-site location after the first such transaction took place.

Even while that was taking place, the line more than doubled during the first half hour after its 8:00 AM local opening time. Some 200 people were in line before that opening, but the line expanded to more than 500 while the first transactions took place.

Adding to our earlier anecdotal report that most of those Colorado early birds had smartphones other than iPhones in their hands while waiting is the anecdotal observation that most of the people going through the line are choosing the US$299 16GB iPhone 3G over the $199 8GB model.