To setup:
1. Download emu48 and ROM.48G
2. Install emu48
3. Copy the ROM.48G file into the emu48 program folder

Emu48
http://hp.giesselink.com/emu48.htm

HP ROM Images
http://www.transnull.com/wp/hp48/

"In mid-2000 Hewlett-Packard released the 48SX/GX ROMS to the public. Previously protected by copyright, the only true way to get a ROM image was to dump the ROM of your own calculator. Some sites provided the ROM but came under legal fire from HP and had to remove them. That said, you can download any of the below ROMS for use in an emulator without owning the actual 48SX/GX calculator."