Hewlett Packard has just released iPhone versions of two of

Hewlett Packard has just released iPhone versions of two of its classic calculators from the 1980s -- the 12C financial calculator and the 15C scientific calculator -- with a third, the 12C Platinum, planned for August.

These apps are pretty much identical replicas, according to MacWorld, with all the old buttons and features available when you view them in the iPhone's wider landscape view. (When you change to the vertical portrait view, buttons for some of the more advanced features disappear.) If a user taps on the HP logo, they even see the list of useful formulas that was once stuck to the back of the device.

At first, it sounded like these calculators might be pure nostalgia pieces, but the pricing says otherwise -- $14.99 for the 12C and $29.99 for the 15C. That's a lot cheaper than the physical devices, which usually cost more than $100, but it's pretty expensive if you're not planning to make real use of those calculators. Looks like they may not be as obsolete as I thought -- especially since the 12C is actually still being manufactured.

[Are you an entrepreneur or executive active in mobile? Join us at MobileBeat 2009, our mobile conference for industry leaders. Sign up soon.]