To read a holodisk in Fallout, left-click the disk in your inventory and hold the mouse-button, then select the open hand-icon (use). Enter the Pipboy, click the status button and hunt down the file from the list on the right.
For locations and transcripts please refer to the individual articles.
Cutscenes ·Holodisks and notes ·Terminal entries ·Vault Dweller's Survival Guide: Pocket Reference Edition ·Dialogue files ·Fallout 3 manual ·Fallout 3 Official Game Guide (Faction profiles ·Wasteland Census · Location profiles: (Tour of The Capital Wasteland ·Tour of Operation: Anchorage ·Tour of The Pitt ·Tour of Broken Steel ·Tour of Point Lookout ·Tour of Mothership Zeta) ·Afterward)
Cutscenes ·Holodisks and notes ·Terminal entries ·Dialogue files ·Fallout: New Vegas manual ·Fallout: New Vegas Official Game Guide (Faction profiles ·Location profiles ·Behind the Bright Lights & Big City) ·Meet the Companions