Here are some links to the newest HP calculator: the HP39gII.
We should pay attention to it, since it is the basis for the newer HP graphical calculators to come.
First, the emulator:
Some math packs to learn:
Learning A-level maths with the HP39gII
A key piece of software if you plan to develop from your computer (attention: this piece of software comes with the last version of the firmware bundled with it - it solves most of the known bugs of the HP39gII)
Several other programs from Calc-Bank, the french resource for calculator programs:
Les complexes sur HP-39Gii
Régression linéaire HP-39Gii
Commandes de programmation utiles sur HP39gII
Eddie B. Shore Calculator Blog Programming Tutorial for HP39GII