After opening up their international sales shortly after crossing the two million mark, Apple’s iPad was even quicker to cross the three million threshold – just twenty more days, another million units sold. Can you spell S-U-C-C-E-S-S?

Apple also announced it had sold 1.7 million iPhone 4 units in the first 4 days of availability, almost making a mockery of iPad’s great run and setting a company record.

Hopefully, this will signal to anyone listening that we’re offiicially in the post-PC era now. America, especially, is moving closer to the European and Asian model where the main Internet access point is mobile. Yes, it took the larger screen of the iPad to convince us, and it’s a great sign that our foreign colleagues and friends also see the new form-factor as valid.

As I talk to clients and potential clients, the world has changed. With the exception of enterprise customers – still stoically soldiering on with their secure, managed, and aging PC-based applications – the new focus is on crafting a new range of experiences adapted to the easy-to-carry, easy-to-access iPad hardware. The set of ideas pouring forth from clients – who in the past wanted, at best, “me too” mobile applications – is really quite exciting. And the iTunes AppStore model for delivering low-priced applications in high volume will assure these new treats will be accessible to a broader range of people.

I’ve enjoyed my iPad since the first day of sales in April, and I’m completely happy with my wifi-only unit. I urge potential customers to consider this option instead of the wifi/3G edition simply because the tariff for 3G connectivity is way too high (in both initial, and on-going, costs). If you need occasion access via 3G, consider purchase of a smart phone that allows tethering – e.g., all the Google Android-based devices can be modified to add tethering. See my blog post on this topic.

Kudos, Apple, for a fine product!