The Wisdom of Crowds

[Currell Berry]

I think Tim Wessman's "20 Essential Things to Know About the HP-49G" is a very useful guide. It links to a large quantity of useful information, including:
1. User guides for 49, 48g, 49G CAS.
2. Documents teaching how to program in UserRPL, SysRPL, and Saturn Assembly.
3. Useful programs
(OT49, Keyman, Emacs, ConfigSaver, Moonlight, APPSman, Libman, Unitman, Stat49Pro, and AutoSimp49).

You can find this guide here: http://www.hpcalc.org/details.php?id=4910 .

Some of the links are dead, but you can usually find the resource by googling. Also, some of the materials are somewhat out of date for 49g+ and 50g. There are some additional resources out there which cover the new features of these ARM-based calculators.