Not really new, but here's a freebie web app I wrote a while ago - it runs in any browser, so you can run it from any PC , MAC, IPhone, Blackberry, etc, that has a browser.
At
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You'll see an entry ( 3rd section down on the left ) :Free Mini PsychroCalc - a cell-phone sized web-based psychrometric state point and 2-point mix calculator. Runs on any device with a browser. Iphone, Blackberry, etc.